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When Opposites Attract
It’s a lazy, rainy, Sunday
morning and you want a no fuss lunch for the family. You’ve got cold cuts
on hand so sandwiches become the obvious answer. As you peruse the fridge
you realize you’re out of mayonnaise. Darn! It’s pouring outside and you
don’t want to schlep to the store in the rain for a stupid bottle of mayo.
Then you remember the cooking show where the chef made homemade mayonnaise.
You copied down the ingredients during one of those “I’ll have to try that
sometime” moments. You know. You get the recipe, stick it somewhere and
then never make it. Now here’s your chance.
One egg yolk, a squirt of white vinegar and
lemon juice, half a teaspoon of dry mustard, a cup of vegetable oil and salt
and pepper to taste. You toss all the ingredients in the food processor
except the oil and whiz them till they’re mixed. Then you slowly drizzle in
the oil with the machine on. You remember that the oil must be added
extremely sparingly at first until it comes together, then poured in a small
but steady stream. Voila! Suddenly, you have mayonnaise. Proud of your
culinary accomplishment, you place the mayo in the fridge. That’s out of
the way and now you can read the Sunday paper with your coffee till
lunchtime.
Lunchtime arrives and you assemble the sandwich
necessities. But when you retrieve the mayo, you notice something is
wrong. Instead of a smooth, creamy consistency, there are little puddles of
oil separated from the primary mass. The mayonnaise “broke” as we in the
culinary world would say. What went wrong and can you fix it? Take out
your notebooks class; Emulsions 101 is now in session.
Mayonnaise, milk, cream, butter, Hollandaise
sauce, vinaigrettes, sauce Béarnaise, etc., are all emulsions. An
emulsion is a blending of fat, usually oil or dairy fat, and a liquid,
usually water based, whereby tiny, even microscopic droplets of the one are
dispersed in the other. The tinier the droplets the creamier and more
stable the emulsion. The problem with emulsions is their constituents are
resistant to intermingling. Oil and water do not mix. Once brought
together their chemical properties exert notable effort to separate and
recombine into their component parts. But there are two types of ammo in
this shotgun wedding to make the marriage work.
The first is agitation. If you combine oil and
vinegar in a jar and shake it vigorously you’ll establish an emulsion.
However, this fusion is temporary. Left to its own devices it will separate
in no time. The oil will float to the top with the water below. However,
there are substances, called emulsifiers, which will maintain the
wedlock. The two most common emulsifiers are mustard and egg yolk.
Mustard coats the oil droplets and inhibits them from recombining. But egg
yolk is even better. Egg yolk contains lecithin and because of its
molecular structure, it adheres to both the water and the oil, and places a
nearly permanent barrier between them.
But nothing is perfect and a variety of factors
can still land the antagonistic oil and water in divorce court. First, if
the oil or fat is added too quickly at the beginning, it will inundate the
water medium and the emulsion will not form properly. Secondly, too much
agitation, (as in any relationship), will backfire and cause it to
separate. Third, extremes of heat or cold, will dissect the union. (For
the mayo, normal refrigerator temperature is OK but if it is too close to
freezing, it’s splitsville). Finally, adding all of the vinegar/lemon juice
at the onset will facilitate the emulsion, but at the expense of forming an
unstable one, (since too much initially will prevent the oil droplets from
becoming as tiny as they should). Thus, the compromise is adding a little
at the start to help the emulsion form and then the remainder after all the
oil is incorporated.
Therefore, our lazy Sunday cook’s mayo could
have separated from 1) adding all the vinegar and lemon juice at the
beginning, 2) over-agitating it in the food processor, (which is why
traditional chefs favor whisking it by hand), or 3) placing it in a fridge
that was too cold.
So then, how do we get the broken mayo partners
to renew their vows? Simple, we send them to marriage counseling to work on
the basis of their relationship, i.e., we start a new emulsion. Whisk an
egg yolk with a pinch of dry mustard in a bowl. Then, slowly mix in the
broken mayo, whisking constantly. If you use a whisk, as opposed to a food
processor, your arm would fall off before you over-agitated it so you
needn’t worry about that. In the culinary world, some marriages can be
saved.
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