I’m quite fond of carbonated water, and last summer I bought a water carbonator so I wouldn’t have to carry all the water home from the shop. The working principle of the carbonater is very simple – a bottle filled with cold tap water is subjected to a pressure of carbon dioxide for a couple of seconds, allowing some of it to dissolved in the water. The result is an instant sparkling water. But even with the carbonation there is something missing. The big difference between my homemade instant carbonated water and bottled mineral water is the mineral content. True, tap water may also contain a number of minerals, but this varies and there are huge regional differences. In Norway most water is very soft (i.e. low in calcium and magnesium) and has a very low mineral content. But tap water rarely has a desirable mix of minerals compared with the really good tasting mineral waters.

Beeing a chemist I started pondering about whether it would be possible to mimic natural mineral waters by adding a clever cocktail of salts before carbonating the water. A real DIY mineral water if you like. The first thing a scientist does these days when a new idea strikes is to google it. I found simple instructions calling for addition of sodium bicarbonate, more elaborate recipes with magnesium sulfate, calcium chloride, potassium bicarbonate and sodium bicarbonate and a recipe for magnesium bicarbonate water where magnesium hydroxide is neutralized by the carbonic acid. But none of these were replicas of actual mineral waters. What I really was looking for was a calculator that would tell me which salts to add in order to clone a specific natural mineral water. But since I couldn’t find this I figured I would have to make my own.

Pure carbon dioxide added to water under pressure

Websites such as Mineral waters have comprehensive listings of mineral contents of several hundred commercially available natural mineral waters from around the world. Major cations are calcium, magnesium, sodium and potassium. Major anions are bicarbonate, chloride and sulfate. In addition a number of trace minerals are present at lower concentrations. One thing I’ve wondered about is which ions contribute most to the taste. The fact that even low concentrations of manganese or iron give an unpleasant metallic taste suggests that the taste of cations is a function of concentration as well as their individual taste thresholds (just like with odorants!). But things are complicated by the fact that iron salts can induce olfactory sensations as well, possibly due to catalytic lipid oxidation. Unfortunately I haven’t found scientific papers on which cations/anions contribute to the desirable taste of mineral water (but please let me know if you know any!). Therefore, as a starting point I decided to begin with some well known mineral waters and assume that their mineral content is quite close to an “optimum”. Furthermore I decided to only focus on the the major cations and anions.

Carbonation equipment from the book Vollständige Anleitung zur Fabrikation künstlicher Mineralwässer

When searching I got a number of hits in old German books such as Über die Nachbildung der natürlichen Heilquellen (1824) and Vollständige Anleitung zur Fabrikation künstlicher Mineralwässer (1860) which discuss how to prepare artificial mineral waters with elaborate descriptions of the the carbonation equipment. Sub sole nihil novi est. Germany has numerous spa towns (Ger.: Kurorte) were the local mineral water was (and is) claimed to have health benefits. In the 19th century some spa towns would evaporate their mineral water to yield the contained mineral salts as a dry residuce for the visitors to bring back home. There they could redissolve the minerals in water and enjoy the health benefits in the comfort of their own home.

One of the books had a recipe for “Selterswasser” (Selters water, named after the town Selters):

This recipe corresponds approximately to a water with the following mineral content (all numbers are mg/L): calcium 58, magnesium 32, sodium 232, bicarbonate 603, chloride 195, sulfate 11. The recipe specifically mentions that iron salts and silicates have been left out, and that the total salt concentration has been somewhat reduced compared to the actual mineral water in Selters. We can compare this with a contemporary analysis of Selters water (mg/L): calcium 110, magnesium 38, sodium 299, bicarbonate 850, chloride 269, sulfate 20. We see that the lower salt concentration claimed in the recipe above is actually true. Not bad considering that the recipe was from 1860!

But back to my calculations: As mentioned I decided to make a spreadsheet that would calculate the amounts of salts to mix in order to replicate a mineral water to be chosen from a list. The salts I settled with are sodium chloride (aka table salt), sodium bicarbonate (aka baking soda), magnesium sulfate (aka as Epsom salt), calcium sulfate (aka gypsum), magnesium hydroxide (a suspension of this in water is often referred to as “milk of magnesia”) and calcium hydroxide (aka slaked lime or pickling lime). The sulfates are available as anhydrous salts, but to avoid any problems with moisture and storage I’ve only used the hydrated salts in the calculator. You can download the spreadsheet for Excel: mineral_water_calculator.xlsx (17 kB). There are five simple steps to use it:

1. Choose which mineral water you want to recreate (click to show drop down list)
2. Selected cations (calcium, magnesium, sodium) and anions (sulfate, chloride, bicarbonate) are shown
3. Compare original with composition of the artificial mineral water
4. Carbonate water and add the calculated amounts of salt
5. If known, please enter the composition of your tapwater here and the recipe will be adjusted according to this

So far I’ve only added the composition of 10 mineral waters to the lookup list. If anyone should have an extensive list of mineral water compositions available in excel readable format I’d be happy to include it in an update

Screen view of my mineral water calculator

Oh – you may wonder if I’ve tried this? No – not yet. I’ve spent my time researching this, not testing it yet. But I will buy the required salts and report back! If you happen to have the pure salts available, why not give it a try?

Update: I’ve written up a short post about no-knead bread in Norwegian – Brød uten å kna – to accompany my appearance in the popular science program Schrödingers katt.

I know – since the NY Times article about Jim Lahey in 2006 the no-knead breads have been all over the internet, newspapers and now even appear in numerous books – this is really old news. But the no-knead breads are really tasty as well, so I hope you’ll forgive me! When I give popular science talks about chemistry in the kitchen the one thing I’m always asked about is the no-knead recipe I show, so I thought it was about time to publish a recipe. Surely, everyone can google it – but regrettably many (if not most?) recipes are given in non-metric, volume based units – even Jim Lahey’s original recipe. And for baking this is really a drawback because the density of flour depends so much on how tight you pack it. Oh yeah, and I will also try to explain why and how the no-knead bread works.

The stretchy gluten which gives a dough its elasticity is formed when the two proteins glutenin and gliadin bind together. Kneading can speed up this process, but in a wetter dough the mobility of glutenin and gliadin increases, and given enough time they can actually manage it all by themselves. That’s why a wet dough needs time to develop the gluten network, but no kneading.

This is to show what 3 g fresh yeast looks like, in case you don’t have a balance that can accurately weigh such a small mass.

I’ve often seen it mentioned that a longer fermentation and/or less yeast gives a richer aroma. I think it’s true, but I’m not quite sure why this is the case. If the flavor compounds are produced proportionally to the carbon dioxide, the easiest way to increase flavor would be to up the amount of yeast. A lower temperature and/or less yeast would only mean that it takes longer to produce the same amount of carbon dioxid and flavor compounds. However, most of the advice I’ve seen about baking suggests that there is a flavor improvement by extending the fermentation time. So to rephrase the question: Why is the desirable bread flavor not proportional to the amount of yeast added? Some claim that the bitter flavor of pure yeast can dominate the flavor of the resulting bread if used at to high levels – but I have never been bothered by yeast flavor, even when using 50 g of fresh yeast for 1-2 kg of flour. But maybe I’m just insensitive to this bitterness? It could also be that the flavor profile produced by the yeast benefits from the lower temperature, but I doubt that one would actually be able to tell the difference in bread (you can easily tell the difference in beer, but here the fermentation may take from days to weeks – see also my post on Baking with hefeweizen yeast). Another possible explanation could be that enzymes, which are present in the flour or slowly produced by the yeast, contribute significantly to the flavor if given enough time. Amylase is one such enzyme which converts starch to sugar. It’s naturally produced by yeast, but it’s often added in pure form to “industrial doughs” to speed things up. Yet another explanation is that a long proofing time will allow a certain production of organic acids by the bacteria which are always present (this of course is what gives sour doughs their characteristic flavor).

The most unusual step in making no-knead bread is that it’s baked in a preheated heavy cooking pan, also known as a Dutch oven, usually made from cast iron. But this is indeed very clever! Professional bakers are lucky to have steam inlets in their ovens, because steam has a heat capacity which is much higher than that of dry air. Because of this the loaf will heat up quicker, giving a better oven spring. But the moist air inside the covered pan does more: as long as the loaf is colder than the pan the moisture will actually condense on the surface of the bread, thereby keeping it moist. This ensures that the oven spring is not hindered by a dry crust. Secondly, this moisture is important for a proper gelatinization of the starch: we are setting the stage for the Maillard reaction.

After about 30 min the lid is removed. At this point one will see the nice oven spring, but also notice that no browning has occured sine the temperature in the crust has been kept below the boiling point due the condensation of moisture on the surface. Once the lid is removed moisture can escape and the temperature in the crust rapidly rises above 110 °C where the Maillard reaction proceeds more rapidly. This is what gives the crust it’s nice brown color and also gives rise to the beautiful smell of fresh baked bread. At this point, the total baking time should be determined by the color of the loaf. When the surface is sufficiently browned your no-knead bread is finished.

Salt is very important, so don’t omit it from the bread. If you try to reduce the amount of salt in your diet – do so by eating less fast food and industrially prepared food. Don’t mess with the salt levels of home baked bread. It’s there for the taste, but it also improves the strength of the gluten network.

No-knead bread (based on Jim Lahey’s recipe)

390 g all purpose white flour
300 g water (77%)
7 g salt (1.8%)
~1-3 g fresh yeast

Mix everything until the flour is completely moistened. Cover and leave for 15-25 hours. Pour onto a floured surface, fold 3-4 times, shape rapidly into a boule, place it on a generously floured cloth/towel seamside down and proof until doubled in size (~2 hours). Dump seam side up into a cast iron pan preheated to 230 °C and bake with the lid on for 30 min. Take the lid of and bake until the crust has a dark golden color – approximately 15 min.

Proofing the loaf on well floured towel

The percentages in the recipe are so-called Baker’s percentages, giving the amount of the ingredients in percent of the flour. The amount of water is often referred to as the degree of hydration. I’ve had good results with a hydration of 77%, but you may want to adjust this depending on your preferences. In fact, it’s impossible to know exactly what hydration Jim Lahey used because of his volume measurements! The recipe posted on the Sullivan Street Bakery’s homepage has a hydration of 80%, but I wonder whether the amounts are calculated or measured. My advice is to start at 77% and then adjust up/down in the range 75-80%. By adjusting the hydration you will indirectly also adjust the size of the pores (more water = larger pores) and the moistness of the bread. The higher hydration will of course yield a more sticky dough, but don’t forget that it’s a no-knead bread, so you’re supposed to handle the dough as little as possible.

Regarding the amount of yeast I’d start with 3 g, but if you feel that it rises to quickly you can lower this to 1-2 g. The main reason for this variability is that the activity (= number of living yeast cells) of fresh yeast decreases with time. Homebrewers can calculate exact pitching rates for yeast based on a ~5% loss of viability per week for liquid yeast. My guess is that compressed yeast is more stable, but I haven’t been able to find any data on it’s viability.

My no-knead breads look a bit different every time I bake them, but that’s OK.

The required hydration depends a lot on flour as well of course! No-knead breads can greatly benefit from substituting some of the white flour with whole grain flours, or ancient cereals such as emmer (farro), spelt, einkorn etc. Whole grain flours tend to bind more water though and develop a less strong gluten network. This last point is well illustrated by my failed attempt to bake a no-knead bread with 100% emmer. The resulting flat loaf is shown in the picture below.

No-knead bread with 100% emmer did not have a sufficiently strong gluten network – the bread ended up very flat…

Further reading:
The Secret of Great Bread: Let Time Do the Work (original NY Times article)
No-Knead Bread (original recipe from Jim Lahey)
Soon the bread will be making itself
Simple Crusty Bread (recipe)
No-Knead Bread: Not Making Itself Yet, but a Lot Quicker
Speedy No-Knead Bread (recipe)
Fast No-Knead Whole Wheat Bread (recipe)
eGullet thread on no-knead breads

A while ago a reader sent me a very interesting question regarding a gelled seafood sauce. It is made by mixing tomato ketchup with horseradish and his question was very simple: Why and how does this sauce gel? He speculated about pectin (which is present in tomatoes), but wondered why ketchup then doesn’t gel on it’s own? And he also noted that horseradish ground with water does not have any gel like properties. So how come they can form a gel when mixed together?


Grated horseradish

The first thing that came to my mind was a previous blogpost on tomato gels with the pectin that’s there. Pectin in tomatoes is highly methylated (HM), meaning that a lot of sugar would be required for it to gel and that gelling is not promoted by calcium. But if it is mixed with juice from carrots or oranges which contain the enzyme pectin methylesterase (PME), the methyl groups are cleaved off (as shown below) to yield a low methylated (LM) type of pectin which will gel more easily, especially in the presence of calcium ions. Could something similar be the case in the gelled seafood sauce?

Once horseradish is cut, enzymes start to break down sinigrin to release allyl isothiocyanate (mustard oil) which is responsible for the pungent taste and the irritating effect on the eyes and sinuses. In biochemistry, horseradish is best known for an enzyme called horseradish peroxidase. I’m not sure if this is the enzyme that is responsible for the degradation of sinigrin, but adding together the bits and pieces my best guess is that some enzyme in horseradish does more or less the same thing as pectin methylesterase, cleaving of methyl groups to make the pectin more prone to gel. I haven’t been able to find any papers on this though, so if any readers know more about his – please feel free to fill me inn! And can you think of other foods where horseradish advantageously could be used for gelling?

Using an Aeropress as a pressure filter to obtain a horseradish extract

Before writing this blog post I wanted to test the gelling, so I took a pieces of horseradish, peeled it and grated it. The gratings were quite dry so I decided to mixed them with some water and then filter the mixture to obtain a horseradish extract. The Areopress coffee maker turned out to be perfect for this (as shown in the picture above). I then mixed the extract with approximately 6-8 times the amount of ketchup and left it in the fridge to gel. A before-and-after picture of the ketchup mixed with the horseradish extract is shown below. If I would make this again however, I’d probably not bother about filtration – instead I would use a food processor with knives to break up the cells in the horseradish as much as possible to maximize the release of the intracellular enzymes.

Ketchup and horseradish extract immediately after mixing (left) and after a night in the fridge (right)

The suggested recipe I received with the question was as follows (more can be found by googling “seafood sauce” or “cocktail sauce” in combination with ketchup and horseradish):

Gelled seafood sauce
250 mL horseradish
4 L ketchup to
25 mL lemon juice

Grate/grind horseradish with a little water. Mix with ketchup. Adjust with lemonjuice (and possibly salt) to taste. Refridgerate. The gelling doesn’t happen until a day or so later.

Wheat beers such as hefeweizen, weissbier and wit are all light beers made from a mix of malted barley and wheat. In southern Germany the typical hefeweizen is fermented with a non-flocculating yeast, and it is not filtered before bottling. This gives the beer a yeasty, bread like flavor accompanied by aromas reminiscent of banan, cloves (we’ve encountered that combo before), coriander and citrus. I’ve just begun to read up on brewing and my first batch of a partial mash hefeweizen is bubling along. As I pitched the liquid hefeweizen yeast into the wort I decided to keep a tiny amount for baking. If hefeweizen beer is reminiscent of bread, why not use the yeast for making bread? In particular I was curious whether some of the aroma top notes characterizing hefeweizen beer would stand out in bread made using the same yeast.

The specific yeast I used was obtained as a liquid suspension from White labs. Their hefeweizen yeast strain (catalogue number WLP300) is identical to Weihenstephan 68. And in case you didn’t know – Weihenstephan is the world’s oldest brewery. Wine yeast is the same as beer yeast (or ale yeast to be more precise) and baker’s yeast – and they are all known under the latin name Saccharomyces cerevisiae (which literally translates to something like a “beer producing sugar munching fungi”). Why bother if they are all the same yeast you may ask. It’s a good question, but despite the common name they are different isolates with very different properties. They certainly have a lot in common: in the presence of air they consume sugars to grow, and in a closed environment without access to air the consumed sugars are instead converted to alcohol and carbon dioxide. But besides this main reaction there are hosts of other enzymes present that produce higher alcohols, aldehyes, acids, esters – all of them volatiles compounds that contribute significantly to flavor. And this is typically where the isolates of S. cerevisia differ. There’s a mind boggling array of beer yeasts available. Take a look at the yeast catalogues of White labs, Wyeast or Fermentis to get an idea of the many yeast strains that are available (note that the lists includes both ale yeasts S. cerevisia which are top fermenting and lager yeasts S. carlsbergensis which are bottom fermenting, meaning that the yeast sinks to the bottom when the job is done). And if this doesn’t impress you – consider the fact that there are thousands of S. cerevisia isolates available from culture collections around the world (ATCC and CBS are among the largest – do a search for S. cerevisiae at ATCC and it tells you to narrow your search because there are more than 5000 hits!).

Apart from the specific strain used the fermentation conditions will also greatly influence the volatile profile: temperature, time, pH, micro and macro nutrients present, and the sugars available all have their say. A general advice for artisan breads is to use only a small amount of yeast (2-3 g) to start with and give the dough plenty of time to develop and rise. This gives a richer flavor compared to using 50 g of fresh yeast to obtain a rapid rise. Since I only started with about a 1/4 teaspoon of yeast slurry I first had to let the yeast grow and multiply. Since S. cerevisiae needs oxygen to grow I added 50 g of water to the yeast slurry and then used a hand mixer to whip in air for a minute or so before adding 50 g of flour. I left the pre-ferment (aka poolish or biga) on the benchtop and the next day there was plenty of bubbling activity. I added more water, whipped in more air with a hand mixer and once again added as much flour as water. This yielded an active starter and all was set for baking.

Hefeweizen bread

Pre-ferment (evening before baking day):
65 g starter (100% hydration)
110 g water
110 g all purpose wheat flour

Baking day:
285 g starter (100%) from day before
466 g water
250 g emmer
485 g all purpose wheat flour
12 g salt

Total dough weight: 1498 g
Hydration: 69%

Add water to starter and incorporate air with a hand mixer to give the yeast a good start. Mix in the flour, cover and leave at room temperature. Next day, mix all ingredients and leave to rise (this may take 1-3 hours). Divide in two, fold over repeatedly and shape into boules. Leave to rise. Preheat oven to 250 °C. Use a baking stone, and generate some steam in the oven during the first 10 min (see picture below). After 10 min, turn down to 220 °C and bake until crust has a nice golden crust.

My current steam setup: I use ice cubes since this prevents a sudden gush of steam towards my hands. The stones serve as a heat reservoir ensuring that the ice cubes melt and evaporate within a couple of minutes. To cope with the heat shock I use a plate of stainless steel to hold the stones. After 10 min I open the oven door to vent out steam and remove the plate with the stones to allow an even heating (no reflection!) of the baking stone from below.

So how did it taste? The bread tasted excellent, but to be honest – I couldn’t detect any aroma that I can’t get using conventional baker’s yeast. The reason for this is probably that other flavors (i.e. from the flour, the baking process etc.) dominate. Another factor is that bread is only fermented for a couple of hours compared to several days for beer. This simply doesn’t give enough time for significant concentrations of the volatile compounds to develop. Lastly, the baking process will drive off the most volatile compounds. Nevertheless, I would still encourage you to try this! I didn’t get the result I hoped for (I was a little optimistic), but it’s a fun experiment to do, especially if you have some yeast left over from beer brewing anyway.

I am by no means the first to try this. But it seems that results are mixed. Some complain about slow rising doughs. But there are also many misconceptions around. One is that some yeasts produce more alcohol whereas other yeasts produce more gas. As long as we’re talking about anaerobic fermentation of sugar to ethanol and carbon dioxide this is plain wrong as ethanol and carbon dioxide are produced in a 1:1 ratio. There is also some confusion with regards to the naming (i.e. beer yeast, ale yeast, brewer’s yeast, baker’s yeast etc. – when all in fact are the same yeast).

Since the bread came out just like bread made with conventional baker’s yeast it’s fair to turn the question around: Do the different beer yeasts really make a difference? I did a quick search in the scientific littereature and found a couple of papers that study the effect of yeast strains on the formation of volatile compounds in beer and wine:

Yeast Influence on Volatile Composition of Wines
Ester Concentration Differences in Wine Fermented by Various Species and Strains of Yeasts
Synthesis of volatile phenols by Saccharomyces cerevisiae in wines
Function of yeast species and strains in wine flavour
Expression Levels of the Yeast Alcohol Acetyltransferase Genes ATF1, Lg-ATF1, and ATF2 Control the Formation of a Broad Range of Volatile Esters

I haven’t had the opportunity to dig really into this, but from the abstracts it definitely seems to be the case that the selection of yeast strains also play a vital role in the resulting aroma profile of the beer.

Oh yeah, one more thing: For this particular bread I used emmer from a local mill, Holli Mølle, specializing in ancient cereals. Emmer (aka farro) doesn’t form as much gluten as conventional wheat (I tried making a 100% emmer no-knead bread which tasted nice but was a fiasco shape wise…), but it does lend a light greyish/brown color to the crumb and also gives the bread a richer flavor. But the use of emmer is of course not a pre-requisite if you want to bake with beer yeast

Looks good and tastes good!

I recently stumbled over “Norwegian egg coffee”. At first I thought it was a joke, but it turned out that this is indeed an “egg coffee” – coffee prepared with an egg! I have never heard about it here in Norway, but the fact that it’s popular among Americans of Scandinavian origin in the Midwest suggests that it could be something immigrants brought with them from Norway (feel free to fill me out on the historic origins of this!). I mentioned egg coffee to my mom, and although she had never heard of it before, she did mention that skin or swim bladders from fish were used when boiling coffee to help clearify it. In fact the Norwegian name for this – klareskinn – literally means “clearing skin”. The English name is isinglass (thank’s Rob!). Could it be that the fish skin originally used was replaced by eggs, perhaps due to a limited availability of fish in the Midwest? After all, both are good protein sources.


Egg coffee is amber colored and you can clearly see some precipitate from the egg-coffe mixture. If serving the coffee warm it seems to be difficult to totally avoid the precipitate unless you filter the finished coffee through a cheese cloth or filter paper. The coffee in this picture has not been filtered yet.

When looking into the chemistry behind this it isn’t as strange as it may sound. Fish skin as well as eggs contain proteins. The addition of proteins while preparing the coffee serves two purposes: 1) it helps the coffee grounds to flocculate, allowing them to sink faster to the bottom of the pot (this effect is probably more pronounced when using eggs) and 2) the proteins bind irreversibly to astringent and bitter tasting polyphenols in coffee to form insoluble complexes that will precipitate. The end result is a clearer coffee with a pleasant and mild taste. The bitterness is only barely noticeable, but the coffee still has enough “body” so it doesn’t feel too thin!

Norwegian egg coffee
80 g coarsly ground coffee (rouhgly 200 mL)
1 egg
100 mL cold water
2.5 L boiling water
250 mL cold water

Mix coffee with an egg and 100 mL cold water to a thick paste. Add this mixture to the boiling water, stir carefully and leave to boil for 2-3 min. Remove pot from stove and add the remaining cold water. Let the grounds settle for a couple of minutes, skim off any floating particles, filter through a fine meshed sieve, a cheese cloth or filter paper and serve.

The first time I made this I stirred quite a bit to break up the big lumps. But I was curious whether stirring had any influence on the amount of fine particles, so I repeated the whole process with as little stirring as possible. The lumps of ground coffee where significantly larger, but I couldn’t really see a difference on the prepared coffee. There was however a small difference when looking at the glasses from below (see picture below). My conclusion so far is that there is not a big difference, and that it’s OK to stir a little at the start to break up the biggest lumps. This will also allow a more complete extraction of the ground coffee.

Difference between much (left) and little (right) stirring as the coffee boils as seen from the precipitate at the bottom of a glass of egg coffee.

The addition of the cold water helps formation and settling of the precipitate. Home brewers talk about a “cold break” when they cool wort rapidly in order to precipitate proteins which have been extracted from the malt. And while we’re talking about beer chill haze also comes to my mind. This is the cloudiness that occurs upon cooling beer, and again it’s caused by precipitation of protein-polyphenol complexes. The effect of adding only 10% cold water to the still hot egg coffee is of course limited, and won’t really be enough to give a “cold break”. But since egg coffee has a pleasant taste even when cold, I have decided to cool a whole pot of egg coffee before filtering it. I may post more on how this turns out later, but initial tasting suggests that it’s going to be a very nice iced coffee!

The interesting thing about the protein-polyphenol complexes is that we also encounter them when drinking wine (a quick reminder here that polyphenols is a group of compounds which includes tannins). There’s a nice experiment you can do to illustrate this which has been published on Khymos previously. When we drink red wine, the tannins react with proteins in our saliva to form water insoluble protein-tannin complexes. A precipitate is formed and as a result, the lubricating properties of the saliva are lost and our tongue feels rough and dry. In other words, we experience the astringency of the red wine. To ilustrate this, try the following (I was first introduced to this experiment at the 2004 International workshop of molecular gastronomy in Erice):

Take a sip of a dry red wine, preferably rich in tannin. Keep the wine in your mouth for 10-20 seconds without swallowing. Spit it into an empty glass and watch how a precipitate forms (this might take a minute or two). Notice how the color changes from red to light red or even pink (see picture below). Rinse your mouth by chewing a piece of bread and drink some water. Take a small sip of the wine that you just spat out (if you dare!). Since the tannins of this wine have already reacted with your saliva, it is as if they were removed from the wine, leaving a fad and flat wine without much taste at all.

Top: red wine. Bottom: formation of precipitate in red wine mixed with saliva.

The saliva flow rate and the concentration of proteins varies from person to person (the latter with a factor of 20). Furthermore the flow rate and protein concentration also varies throughout the day and is also influenced by what you are eating/drinking and even by the smell of food. As a consequence, a person with a high saliva flow rate and/or a high concentration of proteins is more likely to approve of a red wine rich in tannins than someone with a low saliva flow and a lower protein concentration. Knowing this, you should not be surprised that wine preferences can be very individual.

In Asia it is not uncommon to eat fruit with salt or even soy sauce. From my own experience, and via friends, I known that fruits such as mango, guava, honey dew melon, watermelon, nashi pears and papaya are eaten with salt. Interestingly salt is used both for ripe and unripe fruit – the latter is especially the case for mango and guava. With unripe fruit I can imagine that the primary motivation is reduction of bitterness. I’ve previously blogged about salt and coffee and how salt in tonic water reduces bitterness – the mechanisms are the same. In addition to the bitterness suppression low concentrations of salt will enhance sweet taste. [1] This would certainly be an advantage in unripe fruit. In ripe fruit there is hardly any bitterness left (or at least I presume that is the case), so here the salt may serve a different funtion. Could it be to balance the sweet taste and give a more savory and complex flavor? Perhaps it could also be explained as increased sensing by contrast amplification?


Nashi pears (Asian pears) are delicious when served in a bowl of salty water!

One particular combination of fruit and salt that I remember from growing up in Taiwan is eating slightly unripe guavas with a beige powder. We would either sprinkle the powder onto the fruit or simply lick it from our hand. The powder had a savory flavor and was a little salty. I can’t remember the name, but from a couple of google searches I’m quite sure that it was a dried plum powder – li hing mui (or just li hing). I see that it’s available from several sellers on Amazon (In fact I just ordered a pack from Hawaii – if it’s the same I used to eat with guavas as a child it will bring back a lot of memories when it arrives!). I found a couple of blogs showing guava with plum powder and masala salt which suggests that there are probably several spice powders used together with guava. The Wikipedia entry on guavas also mentions them being eaten with soy sauce and vinegar (occasionally with sugar and black pepper) on Hawaii, and with a pinch of salt and cayenne powder/masala in Pakistan and India.

Guavas taste even better with a salty/savory dip! For the picture I combined ground star anis with salt and sugar.

As I started to search for combinations of fruit and salt I was overwhelmed by all the different combinations I found. Salt (and other salty food items) are often mixed with other ingredients such as chili or lime. Here’s a small selection of what I found in no particular order:

salt + sugar + chili (Prik-kab-klua)
salt + sugar + chili + lime (Muối ớt)
salt + chili sauce
salt + masala
salt + cayenne
soy sauce
soy sauce + vinegar (+ salt/pepper)
fish sauce
fish sauce + sugar + chili
fish sauce + black pepper
tajin = salt + chili + lime juice
kiam-muy-hoon/kiamuy
li hing mui (dried plum powder)
dried plum powder + sugar
bagoong (salted shrimp paste)
prosciutto
…

One of the few many salt + fruit combinations that has made it to Europe: prosciutto ham with honey dew melon (and some drops of balsamico syrup)

Other more specific fruit/salt/savory combinations I found were:

bananas and guavas with salt and fresh pepper (served in India)
chili salt with fruits such as Granny Smith apples, plums or oranges.
peaches with chili/lime/salt
pomelos with salt and red chillis
Hawiian margarita with Ling Hi Mui powder
…

It seems that eating fruit with salt is far more common in warm countries where an additional intake of salt is recommended due to perspiration. (Update: Lisa comments on her Swedish blog that it could be due to the fact that there are more supertasters in Asia – they are more sensitive to bitterness, hence the additional use of salt) And I admit that my craving for salt does increase when it’s warm. But there is more to this than physiology – the few combinations I have tried are indeed mouth watering – even when tested in cold Norway. And thinking about it, it is really fascinating how plain table salt – one of the simplest (chemically speaking) ingredients we have in the kitchen – has such a repertoire in combination with fruit. There is certainly a lot to try out in the kitchen now – and perhaps some inspiration from Asia for chefs as well?

If you know about or have tasted other fruit + salt combinations, please leave a comment in the section below

Reference:
[1] Keast, R. S. J.; Bresling, P. A. S. “An overview of binary taste-taste interactions” Food Quality and Preference 2002 (14), 111.

In my everday cooking sage is really underutilized. The only dish I can think of with sage that I’ve prepared during the last couple of years is potato gnocchi. So this was indeed the most likely candidate for experimentation in this month’s TGRWT #21. Potato gnocchi are one of those dishes that I suddenly feel a craving for, and I make it every now and then. When I get things right the gnocchi have a very light texture which fits nice with the melted butter and cheese. This time I decided to incorporate the peanuts into the gnocchi and apart from that stick to the original recipe.

While cooking I tried to chew some peanuts with a sage leaf, and this was a quite remarkable experience. The roasted peanut flavors blended into the sage, and the sensation was stronger than what is usually the case from the previous TGRWT rounds. When tasting sage by itself it will actually remind me of peanuts and vice versa. The last time I had a similar strong sensation was when combining roasted cauliflower with a cocoa agar gel.


I used a mini-food processor to grind the peanutes to a coarse powder.

Gnocchi with peanuts and sage
1 kg mealy/floury potatoes
100 g roasted peanuts
50 g butter
1 egg
250-300 g flour
1 t salt

For serving:
melted butter
chopped sage
grated parmesan
black pepper

Grind peanuts to coarse powder. Boil (or bake) potatoes (preferably unpeeled) until soft. Drain. While the potatoes are still hot, peel them and mash them. Add peanuts, butter, salt, egg and about half of the flour. Mix. Slowly add more flour until you get a soft and slightly sticky dough. Use as little flour as possible, but remember that with less flour the gnocchi are more prone to fall apoart (the added egg helps bind the gnocchi together by the way). Make a roll, approximately 2.5 cm in diameter and cut 1.5 cm pieces. Press against the back of a fork for the characteristic pattern, and place the gnocchi on a towel sprinkled with flour or semolina. Bring a large pot of salted water to a slow boil (is the salt really necessary here?) and cook the gnocchi for 2-3 minutes, or until they float to the surface. Remove from the water and drain. Serve with melted butter, chopped sage and plenty of grated parmesan and ground black pepper.

Gnocchi ready to be cooked. Use too much flour in the dough and you get boiled lumps of flour. Use too little flour and your gnocchi will fall apart.

Verdict: The amount of peanuts used gave a noticeable, yet mild nutty flavor which actually fitted the gnocchi quite nice (for future gnocchi attempts I can imagine even trying other nuts as well, such as hazelnuts or walnuts). The sage works very well as an aromatic and fresh component together with the more “heavy” flavors of potato, butter and parmesan. And frankly, I must say that the gnocchi were a success! I’ll make a note in the cook book that adding 100 g of peanuts works nice so I won’t forget the next time I make potato gnocchi.

A quick search over at The good scents company reveals that the butyraldehyde occurs naturally in both sage and roasted peanuts. But as I’ve pointed out several times previously – as long as we don’t know the impact odorants it’s impossible to tell whether this is the compound that ties sage and roasted peanuts together or not. If you’ve done litterature searches for impact odorants of roasted peanuts and sage, please tell me about it in the comments

An updated version of “Texture – A hydrocolloid recipe collection” is now available for download (version 2.3). The longer I work on this, the more I realize that it will never really “finish” – there’s always more to add. And believe me – my todo list is still quite long (and I even have some feedback which I haven’t had time to incorporate yet). But I thought that since it’s more than a year since the last update, it was about time to share with you the things that have been changed. Major changes and updates include:

Pictures: This is the biggest visual change! Some recipes are now equipped with pictures which may give you an idea of the texture AND they indicate that the recipe has indeed been tested. But I need your help to add more pictures to the recipe collection (please follow the link to read more about how you can contribute pictures)! And of course - a big thanks to those of you who have already contributed your pictures!

Recipes: Recipes have been added and the total number is about 310 now. I’m getting a little more picky now with regards to which recipes I add. Ideally each new recipe added now should illustrate something new.

I should mention that I’m very grateful for feedback from readers and users of this recipe collection. Thank you very much with helping me improve the document! If you find typos, wish to comment on something or have suggestions on how to improve the collection, please do not hesitate to write me an email at webmaster (at) khymos (.) org or just write a comment in the field below.

Please head over to the download page for the links.

As mentioned in my previous post on The Flemish Primitives 2010 (TFP2010) two chefs had taken their inspiration from Asia. Peter Goossens had come across high pressure processing during a study trip to Japan, and had developed this further in cooperation with Stefan Töpfl. Korean born Sang Hoon Degeimbre (of L’Air du Temps) on the other hand had returned to his roots to study kimchi, the ubiquitious Korean staple food. It is a pickled dish made of vegetables with various seasonings, and it is a very common side dish in Korea. In fact, it’s so common that Koreans say “kimchi” when being photographed, just like we say “cheese” in English.

Sang Hoon’s idea was to take the basic concepts and modernize them. Central to the preparation of kimchi is the lactic acid fermentation, using lactic acid bacteria. And in this sense kimchi is closely related to miso, kvass, kapusta, kefir, yoghurt, sauerkraut and sour dough bread – all of which involve fermentation of sugars to lactic acid. And as a commenter mentioned, I should not forget sour beers such as Flanders red ale.

The science was very much integrated into this years event, and to help him with the science of lactic fermentations Sang Hoon had teamed up with Xavier Nicolay from the Meurice institute. Xavier briefly mentioned several scientific papers on Kimchi, most of which you can find by doing a quick google scholar search on kimchi). However, from what I manged to pick up during the presentation nothing from these publications was actually applied in the cooking being done.

Traditional home made kimchi. Photo by J.W. Hamner (CC by-nc-sa).

A lactic fermentation induces several changes in foods. Firstly the acidification aids the preservation as food spoilage microbes generally can’t grow at low pH. Important flavour changes include the lactic acid with a hint of carbonation and other fermentation products such as diacetyl and ethanol. The texture of lactic fermented products is also quite unique as the vegetable or fruit becomes tender without beeing oversoftened. In fact they retain a remarkable crispiness. Interestingly the colors turn brighter, and in some special cases even change (green garlic was the topic of Harold McGee’s first column for the New York Times)

Sang Hoon used the following procedure when preparing his modernized kimchi:

• blanch vegetables (this releases sugars for the fermentation)
• add 1-8% salt
• add a lactic starter (no specific info was given on type and source – hints form readers are welcome!)
• vacuum pack – this is definitely a novel use for your sous vide plastic bags (compare with traditional German way of anaerobic fermentation in “ceramic pot” with water lock rim)
• the vacuum pouches were then left to ferment for 1 week @ room temperature
• to aid creation of flavors starch was added
• yeast autolysate was also added for flavor
• final preparation was clarified in a centrifuge

As a result, Sang Hoon had arrived at a “more sturctured” kimchi (sorry – no picture as of now, but the blog Cuisiner en Ligne does have a nice picture of the finished kimchi inspired dish).

For comparison you may check out these kimchi recipes. Note that none of these uses specific starters (i.e. starting culture of lactic acid bacteria). They all rely on the bacteria naturally present on the cabbage leaves.

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I also visited The Flemish Primitives in 2009. You can read more about that in my four posts from last year: The Flemish Primitives: A travel report (part 1), Chocolate surprise (part 2), Heston Blumenthal (part 3) and Glowing lollipops (part 4). Final note to readers: This year my travel expenses were covered by TFP and the tourism bureau of Brugge.

Miss Silvia is full of surprises! She’s been around the house for a year, but only now did she reveal one of her hidden capabilities. Did you know that you can make scrambled eggs with the steam wand of your espresso machine? Me neither. It’s a brilliant idea and one can wonder why no one has done this before. I mean, espresso machines have been around for a while. And as it turns out – according to Kelly’s comment below this was done in San Francisco back in the 90′s. It seems as if the credits for rediscovering these scrambled eggs should go to Chef Jody Williams (and thanks to Jessica at FoodMayhem for posting this). I’ve tried it several times and it works very well. I’d even say that this gives you another reason to purchase an espresso machine with a proper steam wand! Many other reasons can be found in my first post about Miss Silvia.

This is how I make the scrambled eggs: I crack 3 eggs in a 600 mL pitcher (normally used for steaming milk) and press the steam button on my Rancilio. After approx. 10 seconds I empthy the wand of water and wait for another 30 seconds to allow pressure to build up before I start steaming the eggs. Notice that I didn’t even whisk the eggs with a fork – the whirling effect of the steam wand is strong enough to get the eggs properly mixed. With my Miss Silvia it takes about 50 seconds before the steam breaks through to the surface. The eggs actually set in the pitcher and I used a spoon to scoop the eggs out and put them on a plate. Scroll to the end of the post for a video illustrating the whole process.

Make sure you clean the steam wand very well after using it for eggs. The best way of softening the protein residues is to immerse the steam wand in cold water.

I have tried to add a little milk to 3 eggs before steaming, but interestingly I wasn’t able to get this mixture to set properly. I say interestingly, because even though the scrambled eggs failed I figured that steaming perhaps could be a good way of preparing custards. Holding the pitcher one has pretty good control of the temperature, and also very efficient aeration. It could even that this is a more robust way of preparing a custard? This needs experimenting – and you are more than welcome to join me! And why stop with custard? How about a sabayon? Basically any egg based sauce could be prepared with a steam wand.

Update (added on October 25th)
In the comments there was a question about what would happen with egg whites. I had 3 leftover eggwhites so I added some sugar and tried to steam them. They fluffed up very fast and I was not able to control the process. I spooned the result onto a plate and as you can see the result was quite regrettable. The whites lost a lot of liquid.

I also tried to make a simple sabayon using 1 egg yolk, 30 g sugar and 60 mL of white wine. I got a frothy texture, but when I poured into a glass it separated quite fast. I think the main problem here is scale – on such a small scale it’s really difficult to control the temperature. I presume that this could be easier to control by tripling the amounts.

[Found via the Norwegian food blog Ordentligmat]