You probably consume emulsions every day. Mayonnaise is the most common, and most dressing are emulsions as well. Emulsion, simply put, is the combination of two liquids that are not blendable. I am sure you have tried this, with varying degrees of success, and sometimes it just separates. So we will talk about them today, and why they are an important part of cooking, so let’s get started.
WHY WE DO IT
t begins with two liquids that you want to combine, in say, a salad dressing. We want the creamy richness that Olive oil may bring, but we also want the bite of a vinegar to come to the party as well. We all know that oil and water don’t mix, so how do we do this? How do we bring together two things that have no business coexisting?
First, we need to understand some of the science that is going on here. Ok, its not deep science, so don’t go away. It is simply that the two liquids are each made up of molecules, and the only way to get them to stay in the same liquid together is to get one to be suspended in the other. We do this through a process call emulsification.
HOW WE DO IT
We all know that if you mix oil with a water based liquid it floats, right? Well our job today is to get the oil broken into small pieces so that it will be suspended. We do this by mixingall of our water based ingredients together, then adding the oil based liquids to it very slowly. I can’t exaggerate the VERY SLOWLY part enough. When we do this in a restaurant, we make a cook use timers to ensure that the process is slow enough.
Traditionally I use a blender, and it can be any one of the four common kinds, a whisk, Immersion, traditional, or a food processor. You will find that some are better for things than others, for instance I would not make a Mayonnaise in a blender, but a food processor works perfectly. A food processor would not do well with a cup of vinaigrette, but a blender is spot on for the job. It is all about agitation and the end product you want.
When you add your oil, use a pitcher with a pouring spout, and pour it in a very this stream, about one eighth of an inch, or the thickness of a pencil lead.
WHAT HAPPENS WHEN IT ALL GOES WRONG
It can, and probably will, go wrong at some point. I get this when making Hollandaise or Mayonnaise sometimes, I am in rush, or I am just not agitating enough. It can happen usually by one of two ways.
The complete fail is the one that we probably all know. It’s when the oil based liquid never even mixes with the ingredients, and it can turn a mayonnaise to look like loose scrambled eggs. Usually this one can be fixed, and that is done by letting it sit, then pouring off the oil component. This can be facilitated by refrigeration that will solidify the oil and cause the separation to hasten.
The gradual fail is when the ingredients have look of incorporating, but then they separate back out after a time. This might get you through the big dinner, but it rarely will hold up over night. There really is not cure for this one, but you can attempt the same as above. Re-blending might work for a few minutes in a pinch, however.
The over – oil fail. This one is when one tries to put too much fat into the product, which over loads the suspension like a 1980 Roadmaster, which causes the extra oil to break out of the emulsion. If you see this happening, stop, pour off the excess, and add in some more of you water based liquid slowly to incorporate it.
WHAT IS GOING ON
Okay, let’s get a little scientific on this one here, well at least as much as I can. The fat molecules need to be suspended in the water based liquid, and they need to have a cushion in between them. In order to do this we need to break the oil based liquid apart as it enters into the water based liquid, which allows the molecules to disperse. If they do not do this, then we get a break. If they do not disperse far enough apart, then they will seek each other out, join up, then repeat that, until the emulsion breaks. T
he picture at the right shows the two liquids, the one called Phase II is the oil, while the Phase I is the water. (Photo from Wikipedia)
(A) is the basic liquid setup.
(B) is the an emulsion that will not hold, and the molecules have no cushion, so they will seek each other out, which eventually leads to C. This is also what it might look like if there is too much oil in the suspension.
(C) is the breaking of the emulsion, when the oil is floating on the top.
(D) is a good emulsion when the molecules are suspended and have enough space around them so they are not attracted to each other. This one will hold up!
TRICKS OF THE TRADE
Go slow. Do not rush the process. If I were adding a 1/4 cup of oil to a cup of vinegar I would expect it to take about 2 minutes in a steady THIN steam.
Be secure. Somehow anchor the vessel if it needs to be. A wobbling bowl or container will not allow you to agitate it well enough.
Watch the emulsion well. Keep an eye on it an be on the look out for any signs of breakage. Stop, let the emulsion catch up, add in a bit of liquid, and continue.
Things like eggs and mustard actually help the process of emulsion. It has to do with the introduction of proteins and how they create a buffer, which I could go into, but let’s not!
Well, I hope you have success as you try emulsions in the future with this little bit of knowledge!