Mayonnaise Question for Food Scientist Types: Temperature, Acid, Safety?

[Chad]

I whipped up a batch of cayenne mayonnaise this morning. I had some leftover roast turkey and wanted a sammich. I was out of mayo. So I thought, "what the hell?" Can't be that hard can it?

Nope. It's a little thin, but damn tasty.

Now for the question. Every book I've checked says to refrigerate immediately. Makes sense to me. A raw egg emulsion at room temperature seems to be a one-way ticket to a lengthy survey of the bathroom decor.

But Alton Brown in "I'm Just Here for the Food" has a sidebar in the food safety section that says to leave fresh mayo out for 8-12 hours. Covered, I assume. His rationale is that the acids in the lemon juice and vinegar work best at room temperature and that they'll be more effective than refrigeration at doing in any nasty bugs that might be lurking. At best, he says, if you refrigerate, bacteria will stop reproducing but won't be wiped out like they will by the acids.

Collective minds, what say you?

Chad

[Dave the Cook]

Unless you left the shell on the egg, I'm with AB. (I admit to bristling a bit at the word "rationale," as what he says is true.)

Yes, covered, but that's to keep airborne stuff (and creatures) out. I don't think it has anything to do with acid doing its work.

[Chad]

Unless you left the shell on the egg, I'm with AB. (I admit to bristling a bit at the word "rationale," as what he says is true.)

Yes, covered, but that's to keep airborne stuff (and creatures) out. I don't think it has anything to do with acid doing its work.

Thanks, Dave! I generally trust AB on this kind of stuff, but this seemed a little weird.

Covered, yes. I was thinking more about keeping my cat, Chester, out of the mayo than airborne contagions, but Alton don't say nothin' 'bout no cover. Seemed an odd omission, so I thought I'd double check.

Rationale 1. the fundamental reasons, or rational basis, for something. 2. a statement, exposition or explanation of reasons or principles.

Didn't occur to me that there would be a negative connotation to the word.

Chad

[Dave the Cook]

Rationale 1. the fundamental reasons, or rational basis, for something. 2. a statement, exposition or explanation of reasons or principles.

Didn't occur to me that there would be a negative connotation to the word.

This is my problem, I think. "Rationale" is just too close to "rationalization" in the dictionary for me to distinguish.

I hadn't thought of kitties, but you're right there, too. Ever since I found a paw print in the butter, I've been more careful.

[jackal10]

Strange you should ask that. I'm just writing the Mayonnaise setion for egci.

It depends on the oil. If you have an oil that thickens in the fridge, such as an unrefined olive oil, it will split.

A refined oil, such as groundnut will be OK.

Escoffier, as always, is definitive:

"Unless it is exposed to too low a temperature, the mayonnaise...never turns, and may be kept for several days without the fear of anything happening to it. Mearly cover it to keep the dust away"

he also says

"It is an error to suppose that it is necessary to work over ice or in a cold room, Cold is deleterious to mayonnaise, and is invariably the cause of this sauce turning in winter. In the cold season the oil should be warmed slightly, or at least kept at the temperature of the kitchen, though it is best to make it in a modestly warm place."

[MsRamsey]

What is groundnut oil?

[=Mark]

The concept that mayo is a common cause of illness and that it will make foods more likely to spoil is a misperception. The sheer amount of oils coupled with acidity cause it to actually have antiseptic properties. If you've ever let a nearly empty jar out of the fridge for a few days you'll note it becomes translucent but does not spoil or mold. In essence you have acidified crisco.

[fresco]

What is groundnut oil?

Peanut oil

[fifi]

The room temperature/acid effect on bacteria makes some sense. They wouldn't be as affected at lower temperatures I don't think. I have to admit that I had never thought about the olive oil solidifying and breaking it. That explains what has happened to me in the past, I just never thought about it because it didn't happen that often. When I do make homemade mayo, I usually use it up right away.