If Richard Wiseman’s fork balancing trick is not challenging enough, why not try the fork balancing trick I did for part 8 (where I encourage experimentation in the kitchen) of my Ten tips for practical molecular gastronomy series. You only need two forks, two skewers, a wine cork and a little patience. If interested you can read more about the physics behind the balancing fork trick.

As the name suggests, the TGIF posts are a little less serious than what I otherwise post here at Khymos. I hope you enjoy it

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]

One of the more curious cookbooks I own is a German one entitled “Kochen und Backen nach Grundrezepten” (Cooking and Baking with Base recipes). It was first written in 1932 and has been updated regularily ever since. Each section typically has a standard recipe which indicates the ratios to use followed by suggested variations (just like The improvisational cook). It also has nice summaries of dos and don’ts (just like BakeWise and CookWise), and what really makes the book stand out is that is so compact yet still comprehensive. It’s one of those books I actually use when cooking. Many other books have a little too much text – you have to read a lot to pick up the key points. Anyway – the reason I mention this is that as I read about the new “Ratio” book by Michael Ruhlman (MR books, MR blog), the German cookbook was the first book that came to my mind.

“Ratio: The Simple Codes Behind the Craft of Everyday Cooking” just appeared this month and promises that it “will unchain you from recipes”. That’s a good thing, because by knowing a couple of basic ratios you can cook anywhere without bringing your recipes. I’m quite fond of books like that and look forward to leaf through it once I get my hands on a copy. Bakers have been using ratios for ages, better known as Baker’s percentages, so the concept is not new. When baking bread, knowing that you need 6 dL for each kg flour will make a decent bread (but not necessarily an exceptional one!). Ruhlman extends the concept and describes 33 useful ratios for the kitchen. One examples is cookies, and it’s as simple as 1-2-3: 1 part sugar, 2 parts fat and 3 parts flour. Add flavor according to taste and baking powder and/or eggs for a lighter texture. Now that’s what I call a short recipe! The only thing that puzzles me is why the book has 272 pages… That’s a good 8 pages to explain each ratio But for an experienced cook the only thing you actually need is the ratio. And if you take a close look at the cover it actually displays several of the ratios. I’ve copied them into the table below so they are easier to read. You can find the remaining ratios (covering Stocks & Sauces, Farçir, Fat-based sauces, Custards) in the Barnes & Noble preview of the book. And if you combine these ratios with some of the flavor pairings from “The flavor bible” you should be ready for a lot of fun in the kitchen!

I recently found an interesting article on how an electric field can be used for maturation of wine (New Scientist news coverage of the article). Applying a AC field of 600 V/cm for 3 minutes resulted in an accelerated aging of wine and according to the authors of the paper, it made “harsh and pungent raw wine become harmonious and dainty”. They observed changes in concentrations of higher alcohols, aldehydes, esters and free amino acids. But I was quite surprised that they don’t say anthing about astringency and polyphenols (tannins). I’d expect some changes there as well, but alas it’s so much more difficult to measure the polyphenols than the low molecular compounds. A sensory panel identified both positive and negative effects of the electric treatment which helped identify an optimum treatment. Apparently several Chinese wine manufacturers are testing the technology on a pilot scale now. Many people have a romantic impression of how wine is made, but the extensive catalogues of “corrective chemicals” available to the modern wine maker should perhaps make you reconsider the romatic idea of wine making. Even professor Hervé Alexandre at the University of Burgundy has given the technology a thumbs up: “Using an electric field to accelerate ageing is a feasible way to shorten maturation times and improve the quality of young wine”. Who knows – maybe you’ll soon be drinking a wine that has been zapped?

Moving from industrial scale wine upgrading to kitchen scale gadgets: In his latest “curious cook” column Harold McGee writes about different gadgets that supposedly can change the flavor of wines. To the better of course. He mentions the Wine wand which is supposed to speed up aeration of wines. The promotional explanation on the web page sounds quite dubious, take for instance the claim that the wine wand can “accelerate the aerating process of wine by replicating the natural frequencies of air and oxygen, and infusing them into the wine”. Complete nonsense! Harold McGee however mentions that he did several blind tests and found that there were differences. I guess we can’t exclude the possiblity that there could be some kind of reactive surface on these wands. From the pictures there seem to be some small (glass?) beads in a hollow cylinder. I can’t find any information about the surface. Perhaps it’s been activated or coated with a metal? In that case we could have plenty of surface chemistry going on. If it’s only glass however – well – then I’d just leave the wine to mature in it’s glass bottle.

The other object he mentions is the Clef du Vin or wine key which is more interesting from a chemical perspective. The active part consists of a metal disc which (in a preferred embodiment to quote the patent jargon) consists of 95% copper, 3% gold and 2% silver. According to the description in the patent application, the device is capable of an “accelerated and gauged oxidation-reduction of the wine”. Dipping the disc into a glas of wine for one second is supposed to equal one year of cellar aging. Metals can catalyze many reactions, and there are many reactive compounds in wine so I wouldn’t be surprised if something happens. Considering the fact that sulfurous compounds (such as hydrogensulfide for instance) are very potent, and that sulfur has an affinity to several metals such as gold, copper and silver it seems plausible that the metal disc may actually remove some sulfides from the wine by adsorption and in turn influence the flavor. However, in the course of one second only a small fraction of the wine has been in contact with the metal disc, so I can’t really see how this should be sufficient. It would in a way be strange if only desirable reactions are catalyzed (i.e. only undesirable compounds are degraded/removed). Anyhow – I’d really like to see a peer reviewed paper on this. For someone with spare time and access to a GC-MS this should be a nice project

A stainless steel “soap” is believed to remove garlic stains from your fingers

Interestingly there is a totally different product that relies on the same chemistry: the steel soap. It is typically shaped like a standard soap bar and consists of plain normal stainless steel. It’s supposed to remove garlic, onion and fish smell from your fingers. It works by rubbing your hands against it under running water. I have one, but to be honest it’s hard to really say if it works or not – perhaps some have more experience with it? I had a friend of mine analyze my stainless steel soap by XPS and he gave me the following elemental composition for the six most abundant elements: 70.6% iron, 18.5% chromium, 8.2% nickel, 1.4% manganese, 0.7% molybdenum and 0.3% copper. This is more commonly known as 18/8 steel where 18 denotes 18% chromium and 8 denotes 8% nickel and it’s what all your forks and knives and other stainless steel tools are made of (which of course means that just about any stainless steel object you have in the kitchen should serve the purpose to remove odor from your fingers). Of the metals present here molybdenum in particular is used industrially for desulfurization of oil. Based on a paper on hydrodesulfurization I speculate whether the mechanism could be something like this:

A proposed mechanism for desulfurization on the surface of a “steel soap”

A sulfur compound exemplified here with a thiol (R-SH) reacts with the steel soap surface and the S-H bond is cleaved. Then the S-C bond is cleaved homolytically to yield radical species. The alkyl radical abstracts hydrogen from the surface and escapes whereas sulfur remains bound to the surface. The surface could be regenerated by removal of sulfur with hydrogen. All in all the chemistry of a steel soap seems plausible to me, but I’m not sure whether the effect is significant effect when it comes to removing that garlic smell from my fingers.

Since I got my immersion circulator in December I’ve discovered that there are two critical questions that always come up as I hold a piece of meat in my hands, ready to cook it sous vide: At what temperature should I cook this? And for how long? Despite the fact that two books were published on sous vide last fall it is the short yet comprehensive guide “A Practical Guide to Sous Vide Cooking” by Douglas Baldwin that I’ve found most useful to answer these questions. Those who have followed the eGullet thread on sous vide cooking will probably recognize Douglas Baldwin as one of the major contributors alongside Nathan Myhrvold. Out of curiosity and eager to learn more I therefore emailed Douglas and asked if he would be interested in doing an email interview.

ML: From your homepage I see that you are a PhD student in applied mathematics, how did you become interested in sous vide?

DB: I have always loved to cook. Before last January, though, I mainly cooked slow food. That is when I saw sous vide mentioned in one of Harold McGee’s NY Times articles. Wow. Cooking meat at its desired final core temperature is so obvious! As a mathematician, I kicked myself for never asking “if overcooked meat is bad, what temperature should the meat be cooked at?” A question which many mathematician would instantly answer, “just above the temperature you want it to end up at.”

A quick search of the web led me to the massive eGullet thread on sous vide cooking. While the thread contains a treasure-trove of practical information — especially Nathan Myhrvold’s posts — it left me with a lot of unanswered questions. Being an academic, I turned to the scientific literature for answers; as expected, I found many answers and many more questions.

ML: Your excellent sous vide resource, “A Practical Guide to Sous Vide Cooking” has a wealth of information. What drove you to write this article? And have you ever considered publishing it in a peer reviewed journal?

DB: Thank you. I’m very glad to hear you find my guide to be useful.

As a scientist, I am driven by two things: an insatiable curiosity to learn everything I can about a topic and the desire to freely share what I have learned with the world (so others can extend and build on what I have done). After spending hundreds of hours researching sous vide cooking and discovering how much of the information online was incorrect (and potentially dangerous), I felt compelled to write up what I had learned and post it as soon as possible. I am still actively working on my guide, and hope to complete another major revision in February.

I have not submitted my guide to a peer reviewed journal because its intended audience is chefs and foodies. Though I did ask a number of food scientists to review my guide for technical accuracy, and I was recently asked to referee a paper for the Journal of Food Science.

ML: From your viewpoint, what is the biggest advantage of sous vide over conventional cooking?

DB: Control. Precise temperature control gives incredible choice over the doneness and texture of meat, poultry and fish. Tough cuts can be made tender. Tender cuts are the same perfect doneness from edge-to-edge. Fish and light meat are moist and flavorful. Pork and poultry no longer needs to be brined to be juicy (because they can be made safe without being cooked well-done).

ML: Do you think sous vide cooking will ever become so common that the equipment will be available in regular kitchen stores? And if yes – when will that be?

DB: I don’t think sous vide cooking will ever be so common that immersion circulators will be sold next to microwave ovens. But I fully expect them to be as common as smokers in 5–10 years. Like smoking, sous vide cooking requires a little knowledge and planning — an easy request of the average Khymos reader, but a lot to ask of most consumers. This is unfortunate, because I find sous vide cooking to be convenient, energy efficient, and versatile.

ML: What kind of equipment are you using yourself at home for sous vide? And how often do you typically cook sous vide?

DB: I use a Minipack-torre MVS31 chamber vacuum sealer and a PolyScience 7306C immersion circulator for most of my sous vide cooking. I usually attach the immersion circulator to a full-size countertop food warmer with a lexan lid I made — the lid limits evaporative cooling and the food warmer speeds the (initial) heating of the water and limits heat loss from the bottom and sides of the water bath. I also have a couple Iwatani butane blowtorches, a used PolyScience immersion circulator, a couple PID controllers from Auber Instruments, a Ranco ETC temperature controller, a FoodSaver vacuum sealer, and a bunch of thermocouples and meters from ThermoWorks.

I eat food cooked sous vide almost everyday. As a single guy, I batch cook most my meat in single servings pouches, rapidly chill and then freeze them until needed. While this `cook-freeze’ sous vide is very convenient, the freezing and reheating of the meat does causes small, but noticeable, degradation in taste and texture.

ML: Have you compared DIY bagging with zip-lock bags, food saver bags and vacuum chamber packs? I know that liquids are challenging with the food saver, but does the bagging method affect flavor (or even texture)? Does the small amount of oxygen in the DIY version have any effect?

DB: For meat, different bagging methods have little or no effect on flavor and texture. The primary purpose of bagging is to allow the efficient transfer of heat from the water (or steam) to the food (while still keeping the food and water separated). Sealing the food in a bag has the added benefit of preventing evaporative losses of flavor volatiles and moisture. Even when using a chamber vacuum sealer, the majority of bags have high levels of residual oxygen. The main difference between using a zip-lock bag and a chamber vacuum sealer is the extent to which the bags balloon when heated; (when heated over about 65C/150F) both bags will start to balloon because of the vapor pressure of the liquid in the bag, but the zip-lock bag will balloon more because the residual air in the bag will also expand. It is important that the food is kept from floating to the surface of the water to prevent uneven heating.

While meat can easily be cooked in a zip-lock or food saver bag, fruit and vegetable compression requires a chamber vacuum sealer. Moreover, zip-lock and food saver bagged vegetables balloon excessively in the 85C/185F water bath they are (typically) cooked in because it very difficult to remove all the air in the bag.

Liquid in the bag is indeed problematic when using a food saver, but is easily solved by freezing the liquids before bagging. (Although, I might add that freezing often traps air bubbles in the liquid which cause the bag to balloon more than it would have if a chamber vacuum sealer was used.)

ML: What are your favorites cuts of meat for sous vide?

DB: With the faltering global economy in mind, I love showing off sous vide cooking’s ability to transform inexpensive cuts of meat into something amazing. Consider the humble chuck roast, a flavorful cut of beef which is usually relegated to stews and hamburger because of its abundant connective tissue. Vacuum sealing, cooking for 24 hours at 55C/131F, and searing to a beautiful mahogany color transforms this humble cut into something akin to prime-rib! Pork shoulder vacuum sealed with lard and cooked for 24 hours at 68C/155C, torn into bite-sized hunks and fried in a little oil is always a hit at my dinner parties. Even the the lowly chicken breast can be made into something moist and flavorful by pasteurized in a 60C/140F water bath (see my guide for pasteurization times).

ML: Is there any meat that you would prefer not to cook sous vide?

DB: I don’t like some types of fish cooked sous vide. When cooked too slowly, the enzymes in the fish remain active and cause the flesh to become mushy. [This can be mitigated by using a water bath temperature 5--10C/10--20F higher than the desired final core temperature and using a needle temperature probe inserted through closed-cell foam tape to determine when the fish is done heating.] Also, fish which is not extremely fresh will taste too fishy because the flavor volatiles remain sealed in the bag with the fish —this is a particularly irksome problem for me in land-locked Colorado.

ML: Some critics claim that with sous vide, even though you brown the surface, you loose some flavor since temperature is kept so low (I believe this applies especially for pork). Do you share this experience?

DB: It is a very reasonable concern, but can be mitigated by quickly searing the meat before vacuum sealing and cooking. While the initial Maillard reaction occurs noticeably above 150–180C/300–350F, many of the subsequent reactions can occur at the low temperatures used in sous vide cooking. Personally, I feel searing after cooking is sufficient and almost never take the time to pre-sear my meat.

ML: From your experience, what is most difficult to achieve when cooking sous vide?

DB: A great sear without overcooking the meat. While a blowtorch works wonders on beef and (most) pork, it tends to burn poultry. A pan with a little oil over medium heat (so the oil is between 150–180C/300–350F) works fairly well for poultry, but may overcook the meat before the surface is golden brown.

ML: With Keller’s recent book “Under pressure” and your guide (and an extremely long thread at eGullet) being available now: Which areas would you say need further exploration?

DB: Sous vide cooking is still relatively young and there are hundreds of interesting questions yet to be answered! Some of the questions I’m currently interested in are: How long does it take all the soluble collagen to unfold into gelatin at 55–65C/130F–150F? What is the role of enzymes when cooking at low temperatures for long times? Is it better to thaw the meat or cook it from frozen? If cooking from frozen, how long does it take to heat a piece of meat (such as foie gras) stored at -80C/-110F? Which foods can be frozen or refrigerated after cooking (and for how long?) without significantly degrading taste or texture? How and why should fruits and vegetables be cooked sous vide? Why does fish retain so many more of their essential fatty acids when cooked sous vide (compared with conventional cooking methods)? . . .

In addition to the many unanswered questions, there are also many topics which are understood but have yet to be discussed in sufficient detail. For example, many people’s intuition about clamp and chamber vacuum sealers is wrong. The importance of food shape in predicting heating times has not been discussed — spherical and cylindrical foods heat much faster than slab shaped food. The relatively fast onset of warmed-over-flavor after the food is removed from its vacuum pouch is absent. And even how large and powerful the water bath needs to be for a given quantity of food has not been discussed.

Hopefully I, Nathan Myhrvold, or someone else will have the time and resources to answer all these interesting questions.

ML: Thank you very much!

An updated version of “Texture – A hydrocolloid recipe collection” is now available for download (version 2.2). There are two file sizes available: screen resolution (~1 MB) and high resolution for printing (~5 MB). Some recipes have been added bringing the total number up to about 270 recipes. Apart from this the version includes corrections of typos and updates of indexes and the supplier list. There is a new index for alcoholic preparations plus a small glossary. Again 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.

English = Norwegian
beef brisket = oksebryst
sirloin = mørbrad
bottom round = rundbiff
round steak = flatbiff
chuck = høyrygg
roast beef = roastbiff
club steak = entrecotè
tenderloin = indrefilet
T-bone = T-ben
boneless strip = ytrefilet
ground beef = kjøttdeig
short ribs = bibringe
flank steak = slagside
stew meat = bankekjøtt

There are a couple of false friends here. The Norwegian translation of “round steak” literarily means “flat steak”, whereas the Norwegian “Rundbiff” which litterarily mens round beef is equivalent to the English “bottom round”. Easy to get confused here…

The suggested temperature range for the roast beef was from 60 °C for a pink interior to 68 °C for grey meat. I settled on 63 °C. I was a little optimistic regarding the timing, so when our guests had arrived and I checked the meat (after 1h 30m) the core had only reached 53 °C. First lesson learnt: meat is a poor heat conductor. I quickly figured that my guests would become very hungry if I were to wait for the core temperature to reach that of the water bath. I therefore turned the water bath up to 68 °C, and put the meat back into the water bath – this time in a normal plastic bag and with a temperature probe at the core. This worked surprisingly well, the pressure of the water pushing out all the air. After another 45 min it had reached 62 °C and I removed the meat from the water bath, saved the juices for the gravy, rubbed the meat with salt and pepper and gave it a quick pan sear with plenty of butter. Despite my bad timing the beef came out extremely moist and tender – I dare say that I have never before achieved such a result with a roast beef in my kitchen! And being my first attempemt at sous-vide with my immersion circulator it was extremely satisfying.

Today I prepared the chicken breast, and I figured that 1h 30m should be sufficient for 700 g of meat. The chicken came out very nice as I served it with fresh pasta, a curry sauce and some salad. Again the meat was moist and tender – and so different from most of the chicken I’ve prepared both at home and been served at restaurants.

I should also mention that I made 68 °C eggs this morning. I left them in the water for 1h. The egg white was very soft – almost runny – whereas the yolk had set but was still very pliable. Comparing this with the eggs over at Fooducation it’s clear that even with constant temperature time does play a role. My 1h @ 68 °C eggs had a white that looked more or less like the white of Erik Fooladi’s 6h @ 65 °C eggs. The are probably several reasons for this, but I guess that the kinetics of protein coagulation are mcuh more complex that one might expect at first. But that’s a different story.

Several comments to my last post asked about pricing and where to buy immersion circulators. Basicallyl any laboratory supplier sells these. And even the simplest models have temperature stability of +/- 0.1 °C or less. Amazon also has a couple of models available from Fischer/Thermo Scientific ranging from around $900-2000.

Oils and fats are long molecules which are mainly non-polar and hence the opposite of water which is a polar molecule. Ethanol which has both a polar and a non-polar end falls in between oil and water. I’ve covered extractions using water and ethanol previously. That water and oil are opposites is easily observed by the fact that they don’t mix, and because of it’s lower density oil floats on top of water. This property allows us to easily separate water and oil.

Volatile molecules – the molecules that we detect by their smell – are mainly non-polar and therefore soluble in oil. This is one reason why foods with fat often have a different and often better flavor compared with their fat-free counterparts (fat of course also influences mouth feel etc.). Everytime you cook with oil it will actually help extract aroma (or smell flavorants) from the food ingredients and deliver these to your nose.

There are several oil extracts used in the kitchen, and the nice thing about them is that the oil extracts aromas and then protects them from the air. This is good as it prevents oxidation of the aroma molecules, but in some extreme cases bad because the anaerobic conditions may promote growth of botulinum spores – more on that in the last paragraph. When the flavored oil is added to a dish you get can immediately perceive the aroma. If the oil is tasted pure it serves as a carrier for the aroma giving a small explosion in the mouth (or nose to be more precise…). Some examples I can think of where the oil plays an important role in extracting and delivering aromas are: pesto, tapenade, mayonaise, aioli, curry paste (and all other spice pastes), chili oil and truffle oil to mention a few. Notice that in most of these the source of the aromas is still present in the oil.

One significant addition to the aroma molecules is capsaicin which gives chiles their pungency. Capsaicin is not particularily volatile so it never reaches your nose, but it certainly does burn your tongue! The funny thing is that the receptor being attacked by capsaicin is a protein which is also sensitive to temperature. So when talking about “hot” food it’s true in a double sense. There is an overlap in how our brain perceives food which has a high temperature and food which is spicy.

The fact that water and oil are non-miscible can be utilized in the kitchen. Oil can be used to extract non-polar compounds from a water phase, and oppositely water can be used to extract polar compounds from an oil phase. In the organic chemistry lab water and oil would be separated with a separatory funnel, but in the kitchen a normal plastic bag will work fine. Check out the pictures and description of how a plastic bag is used to clarify butter over at Cooking for Engineers.

Although most of the aroma molecules will be present in the oil, a tiny amount will remain in the water. It is possible to measure how molecules partition between oil and water, and instead of cooking oil one uses octanol. You can read more about the partition coefficient K_{octanol/water} over at Cumbrian food lab.

To start experimenting with this in the kitchen I suggest you start with some colored foods. Flavor compounds are normally colorless so it’s hard to see where they end up. One can put up a very general list of compunds responsible for the color of foods:

We can start with blueberries. For the experiment I used a blueberry syrup and mixed it vigorously with oil using an immersion blender. However, when the phases separated the oil was colorless and the waterphase was still blue. The reason for this is that anthocyanins which give blueberries their nice color are water soluble. No matter how much you blend the blueberries with oil the blue color will remain in the water phase.

I should have waited longer to allow the phases to separate properly, but notice the oil clinging to the glass wall in the right picture – it’s totally clear without any traces of blue/purple color.

For our next experiment we will use carrots or carrot juice. Add some oil and mix with an immersion blender to extract the carotene. What you observe now is that the oil phase turns orange/yellow. The reason for this is that the carotenes are oil soluble. If desired one can separate the two phases with a plastic bag as mentioned above.

Extraction of carotene from carrots. Pictures: 1) I finely grated carrots, 2) Blended them with water and filtered of the remains – the water phase was then layered with plain cooking oil 3) Water and oil were mixed with an immersion blender and the phases left to separate, 4) A plastic bag serves as a separatory funnel – cut a small hole to let out the liquid. The water phase turned grey, probably because I left it at room temperature to allow the phases to separate (1-2 days).

Now that the effect has been demonstrated with food colors it’s time to move on to tastes and aromas. The four basic tastes are all soluble in water, whereas the pungency found in chiles for instance is soluble in oil. Aromas or smell flavorants however are primarily soluble in oil. To test this one can take some clear meat stock, add oil and taste the water and the oil phases separately. The water phase will be salty, and also have a little meaty flavor (our nose detects the tiny amounts of oil which remain in the water water phase, even if no oil droplets can be seen – and of course there are also umami flavorants in the water phase). The oil phase will not be salt at all and have a strong meaty aroma.

Even though you seldom will go to the extremes of separating oil and water phases, it can be good to think about where your aromas goes when you cook. And so you won’t forget I rewrote the first few lines of the Shoop Shoop song:

/ D7 – C7 – / D7 – - – /
Can you tell me where the aroma goes
and how it enters into my nose?

/ Am7 D7 Am7 D7 / / G Em7 Am7 D7 / G C D – /
It’s through the oily phase – Oh yeah, into the nose
In the water phase? – Oh, no, that’s just the salts
If you wanna know where the aroma goes
It’s in the grease, that’s where it is

(aroma should be pronounced more like ‘roma when singing)

–

Somes words about safety: When infusing spices, herbs or garlic – think about the fact that you create anaerobic conditions. If pH is above 4.6, the oil is kept at room temperature, and Clostridium botulinum spores are present you might be bad off (botulinum toxin causes botulism). There are sites that cover this in greater detail. Perhaps the easiest way of preventing the growth of botulimum spores is by adjusting the pH with an acid such as phosphoric or citric acid (that would be the pH of any water phase present as they are not soluble in the oil).