Why isn't my vinaigrette emulsifying properly?

Question

I made a vinaigrette tonight. Normally, to make one, I put vinegar and oil in a mason jar and shake to mix. This usually seems to emulsify the mixture properly and it holds for a while. Tonight, I made one with 20% red wine vinegar, 20% champagne vinegar, 10% dry sherry, 50% Greek olive oil, and nothing else. I found that after shaking, it started to separate within about 30 seconds, being completely split again after about a minute. Why did this particular mixture not stay in a stable emulsified state?

Asked by yossarian

Answer

As Michael mentioned, a shaken vinaigrette is only going to stay together primarily while you're shaking it. If it's been staying together long consider yourself lucky all the other times...this time was what should be "normal".

The more particulate such as herbs, mustard, spices, etc. that you have in a vinaigrette the quicker it will emulsify and the longer it will stay emulsified. The particles of spice and herbs act as physical barriers that help to interrupt the droplets of oil so that they aren't able to coalesce and come together as they can when you have just oil and vinegar/acid.

When doing vinaigrettes by hand using a whisk, start with your acid and add the salt along with anything else, leaving the oil last. Adding salt to the acid component will help it to better dissolve so you get a truer reading on the flavor. When it's added last as it's usually written in most recipes: "season to taste with salt and pepper", the salt usually hasn't dissolved by the time you taste it and you're much more likely to add too much, resulting in a dressing that's a bit saltier than you might like.

The manner in which you drizzle the oil and manner in which you whisk it when doing by hand, are also important factors. When whisking vinagirettes by hand, drizzle the oil form a higher level so that as it hits the bowl you have a finer stream that's easier to emulsify. Also, use a back and forth "zig-zag" motion rather than a circular whisking motion. The "zig-zag" motion will allow the wires of the whisk to better break up the oil into droplets and emulsify them with the acid. Using a circular motion creates a vortex in the center of the acid where the oil tends to pool, resulting in an oily vinaigrette.

The great part of using an immersion blender (aka stick or wand blender) is that EVERYTHING can go in at once. Use a container that's deeper than it is wide (such as 2 cup liquid measure) so that there's plenty of depth for the liquid. Garlic, shallots and herbs can even go in whole. The immersion blender will blend up your garlic, etc. and emulsify the oil with the vinegar. An immersion blender or a standard blender provide you with a the most stable vinaigrette.

Answered by Darin Sehnert

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How to make mayonnaise with a cooked yolk?

Question

I have heard of mayonnaise made with cooked yolks before, but was suspicious of it. Now a user posted another question with a link to a recipe which shows the making steps. It shows the making a mayonnaise with a hard boiled yolk, emulsifying 150 ml of oil with a single yolk (and as far as I can tell, no additional liquid - the text is in Romanian). The mayonnaise in the picture looks nicely emulsified and smooth.

How is boiled-yolk-mayo made? What is the best ratio? Should I follow a different method than with raw yolk? How different is the result from normal mayonnaise?

Asked by rumtscho

Answer

I went ahead and tried it. I used hard-boiled yolks, as a soft and slimy one would be not really different from making the mayo in a waterbath. It turned out to be incredibly fickle.

The first try, only yolk and oil, with immersion blender, split immediately and never recovered. The second try was supposed to incorporate the bad emulsion. I first made a paste from the yolk with a few milliliters of lemon juice and water, then started adding the bad emulsion, beating with a mixer this time. I got a thick suspension of yolk particles in oil, but it wasn't emulsified.

The third try worked at first. Again, I started with yolk and water and lemon juice, and then added the oil in really tiny amounts, half a teaspoonful at once. I used the mixer again. It emulsified, but was runny. I kept adding oil, and it was a nice emulsion, but very soft, runnier than soft peaks, like a batter. And then, one of the teaspoons of oil broke the emulsion completely :(

I don't know how the emulsion in the picture is made, maybe the sources I have heard of forget to mention that the yolk shouldn't be hard boiled (mine was longer boiled than the one in the forum picture). If this is the case, then obviously there is nothing unusual happening here - the yolk retains some of its emulsifying power even after boiling (I suppose it is the lecithine), but many of the substances which are actively helping the emulsion when heated around 70°C don't work any more. So, working with cooked yolks is possible, but much harder than the normal heated raw yolks. Which makes me think that there is no reason to try further to use cooked yolks.

I can't comment on taste, didn't try the emulsion before it split. After splitting, the yolk-containing oil is still usable as a bread dip, but doesn't taste well enough to be made on purpose.

Answered by rumtscho

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Why does Béarnaise separate as opposed to crème brûlée or lemon curd?

Question

When making creme brulees in the oven, they are heated to something like 100° C, or over. When making bernaise, heating it like that is a sure way of making it separate.

As far as I've understood, it is the vinegar and the fat that separates, when the protein in the egg coagulates, and of course there is no vinegar in either creme brulee or lemon curd, but the protein still coagulates. Still, the result is silky smooth.

Why is this? All I have are guesses, and some small amount of culinary science to shed some light on this would be greatly appreciated.

Answer

I think that there are a few different concepts being conflated here - let's try to clear those up before getting to the heart of the matter.

First of all, acidity causes just about any dairy product to curdle. That is precisely how cheese is made. Acidity, salt, and heat are all catalysts in the curdling process. This does not, however, affect clarified butter, because curdling is a result of the milk proteins coagulating and binding to each other, and true clarified butter is just the butterfat - there is no milk protein left. Based on that, we can conclude that vinegar is definitely not the important factor, which is further evidenced by the fact that lemon curd will also have a fairly high acidity due to the citric acid in lemon juice.

Crème brûlée is also not heated to 100° C, or even close to it. Dairy products burn very quickly when they approach that temperature. Many recipes for crème brûlée or crème caramel - and IMO virtually all of the good ones - will have you use a bain-marie (water bath) for the express purpose of temperature control. Since egg yolks begin to coagulate at 63° C (145° F), a crème brûlée doesn't need to be heated much higher, although there are many recommendations for the optimal temperature that seem to average around 75° C (around 170° F). If you try boil a crème brûlée, it will almost certainly burn and quite possibly curdle too.

For this reason, I believe that at least part of the difference is simply in your perception of the heat. Ovens heat much more slowly than stoves. Béarnaise (or the very similar Hollandaise) doesn't get heated all the way to 75° C, but it does get heated up to around the 63° C coagulation temperature of egg yolks, which really isn't that far off. You might see the surface of your crème-whatevers sizzle a bit, but that doesn't mean the entire pastries are at the liquid's boiling point; if they were, they'd be ruined.

The rest of the difference is sort of what Bruce's explanation is saying, although I think he's got it backwards, and the reported Julia Child ratio is way off (it should be 2 egg yolks per 3-4 oz of butter, which is only 90-120 mL). The amount of egg yolk (which acts as an emulsifier) relative to fat or dairy is important, but in order for the answer to really make sense, it's also important to understand why.

Egg yolks and butter-fat compose an emulsion of proteins and fat. The fats don't do anything special in response to heat, but the proteins coagulate, and in the process they will try to bind to each other; given a generous enough amount of egg yolk emulsified with butter, if you (a) heat up the yolks past the coagulation temperature and (b) don't keep them extremely well-dispersed, you'll end up with buttery scrambled eggs.

When making crème brûlée - or any custard - you want full coagulation of the egg yolks, because the relatively small amount of protein-packed yolks (typically, anywhere from 10% to 20% of the heavy cream by weight, which is only 4-8% of the fat by weight) is easily dispersed, and the individual molecules can't get close enough to each other to coalesce; instead they form a semi-firm but sparse network around the fat, much like what a meringue does around air.

On the other hand, Béarnaise and Hollandaise are supposed to be sauces. You're trying to thicken but not coagulate the eggs - in other words, allow a very weak protein network to form. To make this partial coagulation have any noticeable effect on the sauce's consistency, you need (relatively speaking) substantially more protein - closer to 30% of the fat. This higher concentration of protein puts the protein molecules in much closer proximity; without constant dispersion (in the form of whisking) and low, slow heat, the proteins will quickly start to coagulate and coalesce, because there's nothing stopping the attraction. This causes flocculation or even outright coalescence of the emulsion, which is the point at which you get that nasty scrambled-egg consistency.

It's got nothing to do with fat:water and everything to do with protein:fat. Fat helps prevent the coagulation of proteins; this principle is applied everywhere including baking, where oil or butter is used to slow down gluten development from flour (not eggs) and keep baked goods from becoming tough and rubbery. The ingredients and cooking method are different in a custard, but the principle is the same.

Protein is the main character in egg-based sauces and in scrambled eggs; the main difference between the two (with custards being somewhere in between) is how much protein, how well dispersed it is, and how much it is allowed to coagulate. Sauces have more protein, less coagulation; custards have less protein with full coagulation.

The difference is not huge, but it's enough to tip the scales if you're not careful.

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How to keep sauce spices in suspension

Question

I make a very simple BBQ sauce for chicken that's composed of butter, vinegar, and an assortment of dried spices (lots of paprika, some cayenne, salt, etc). My problem is that the spices won't remain in suspension; they drop to the bottom very quickly. I have to stir a lot before each application, and even if I do the last bit in the pan is much more concentrated than the first.

I'd like to be able to make larger batches and refrigerate it for future use, but that's out of the question since it would harden with all the spices at the bottom.

How can I get the spices to remain in suspension without affecting the taste?

Answer

The easiest solution would be to add a thickening agent to your sauce. Which agent will depend on how much you are willing to have the texture of the sauce change in order to achieve a good suspension. One of the easiest methods, if you are also willing to alter the flavor profile in the direction of South Carolina or Germany, would be to add mustard. Natural emulsifiers in the mustard will help keep the butter from separating and also provide a bit of thickness to keep the spices in suspension. If you don't want to change the flavor profile, many recipes intended for the home kitchen suggest thickening the sauce with cornstarch. Most commercial sauces will use a combination of modified food starch (which isn't readily available to the home cook) and xanthan gum (which is becoming increasingly available at most mega-marts), the usage of which has been discussed on this site previously [here and here].

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Garlic and oil emulsion

Question

A few days back I was making garlic bread. I had pressed garlic into olive oil, added a little salt, and forgot about it for a good half hour or so. When I came back to it, I stirred it up a bit, and it seemed to thicken slightly. Intrigued, I whisked some more and it ended up extremely thick, with self-sustaining peaks.

Tonight I tried to recreate this phenomenon, and it really didn't do anything to speak of. After whisking hard for about 45 minutes, I still basically had a bunch of pressed garlic sitting in a pool of olive oil.

What did I do wrong the second time, and what did I do right the first time?

Answer

Congratulations, you accidentally made allioli, a Catalan emulsified sauce requiring only garlic and olive oil to thicken and emulsify. Unfortunately, it's harder to make and less stable than the other aiolis (garlic mayonnaises), which include egg yolks as emulsifiers. This is probably why you are having difficulty replicating it.

To make it more consistently:

1. Smash the garlic up into a fine paste before adding oil
2. Add oil slowly, starting with a drop at a time, and mixing rapidly until incorporated (traditionally this is done with a mortar and pestle, but it is easier with a mini-whisk).
3. Optionally, cheat and add an egg yolk (beaten) for every clove or two of garlic (it is no longer a true allioli though).

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