Cooking food in dangerously caustic alkaline solutions

How in the world did people start

Cooking food in dangerously caustic alkaline solutions? olives soaked in lye, fish soaked in lye, eggs soaked in lye, bread soaked in lye — why did people first start doing this? i mean, acids can burn your skin off too in sufficient strength and concentration, but it's easy to understand how they ended up in food — we like how they taste.

We like the taste of sour things,

Within reason, and there's probably a lot of reasons for that, but one is certainly that we need vitamin c, ascorbic acid.

If we don't get it, then we get scurvy and we die, and so we evolved to like the taste of sour fruits, for example. That makes sense. But on the other side of the pH scale, bases usually taste bitter, and scientists think we evolved our bitter taste sensation, chiefly, as a warning. Bitter things are likely to be toxic, so in this lye water we have a basic solution that can cause chemical burn and tastes bitter and gross. So, how did it end up in food? Well, this is a topic anthropologists have explored a little bit, particularly as it pertains to traditional corn, maize processing here in the Americans. But nobody really knows, and it probably depends on a case by case basis. I'm going to talk about one possibility today with you that I'm pretty sure played a role.

A basic solution is one that contains a lot of hydroxide, which is a negatively charged hydrogen and oxygen ion. An acidic solution, in contrast, has a lot of positively charged hydrogen. Anyway, one surefire way that food and bases got mixed up is fire. Ashes are full of bases, particularly ashes made by the burning of certain plants, like hardwood trees. Hardwoods reproduce via flowers and fruits and such. Flowering and fruiting requires a lot of potassium, so there's a lot of potassium in the wood, and when you burn the wood in a really hot fire — you drive off most of the carbon in the water, and assorted volatiles — you're going to be left with a powdery white ash containing potassium carbonate, potash.

Time out to say that potash is one of the terms we're going to be using today that has like a lot of different definitions.

It doesn't just refer to one thing. Potash also refers to various potassium bearing minerals that are mined and used as fertilizer among other things, but the name descends from a scenario like this, where ashes and pots mingle. When the ash gets in the water, chemical reactions ensue that raise the pH of the water. You get a basic solution. It seems possible to me that one day some ancient person was boiling some food on or near a very hot fire, the wind was blowing and that supplied lots of oxygen to the fire making it burn even hotter, but it also blew lots of ash around and a ton of pure white ash got into the water — enough to raise the pH significantly.

Then this ancient person noticed that the ash seemed to make the food cook faster. High pH does all kinds of things to break down starches, and pectins, and proteins, and a potato or something cooked in a basic solution is going to soften much faster.

Anyway, ashes. The fire is done and cooled. I will sift the remaining charcoal out of the white ashes and then I will dump the white ashes into the nearest clear glass container, just so that you can see what's happening in there. The urn shape is unfortunate — I swear this isn't Grandma, kids. Anyway, I'll pour in some soft water. People historically would've used rainwater, which is generally pretty soft. My tapwater here is hard water, meaning it's got lots of dissolved minerals and such, and so stir in the bottled soft water.

And as those alkaline salts dissolve out of the ashes, all of the solids and the insolubles and such, they're just going to fall to the bottom. That's probably mostly calcium compounds and carbon at the bottom. Now I can just pour my lye water off the top. Lye is another one of these words that means a few different things. Nowadays, it generally refers to sodium hydroxide, which is a different thing, although actually you probably would get a little sodium hydroxide out of wood ashes. But historically, lye just means kind of any basic solution, any alkaline solution. And actually the word lye is an old Germanic word that just means bath. I wonder if maybe it came to be called that because lye water feels warm on your skin.

I mean, a light lye solution might feel warm on your skin — a really intense one will sear your skin right off. But it also might just be that lots of natural hot springs that people used to bathe in are naturally basic. Regardless, historically, lye has referred to all kinds of basic solutions, or the crystals you can precipitate out of these solutions by boiling all the water off. This is probably mostly potassium hydroxide lye that I'm filtering off that I made with the wood ashes. It happens when potassium carbonate from wood ash gets wet. If we boiled all the water out, we'd have caustic pot ash. If we baked it in a kiln to burn off the impurities, we would have pearl ash, which was historically used as a leavener for bread. I'm not doing any of that — I'm just trying to raise the pH some more by concentrating my solution.

Look, we've still got impurities in there. pH is a little over 10, which isn't super high. That's not like yoga pants in winter basic; that's just like peacoat in winter basic. You need a lot of ash to make really powerful lye water. But this is strong enough to prove my point. I'm going to boil a little potato slice in some of this weak lye water for five minutes. And this slice, I'm going to boil in the same exact level of normal water. Normal water potato slice is on the right.

This potato is kind of brown because bases lower the temperature at which the maillard reaction occurs. That's why we soak pretzels in lye. It allows them to brown thoroughly on the outside without overcooking the inside. Anyway, that's part of why this potato is a little brown, and check how easily I can tear it apart. This slice, we cooked just as long in plain water and I can't even begin to tear it apart. Ashy water cooks things faster, and I think ancient people would have noticed that and taken advantage of it. Ancient Americans might have noticed the same effect on corn, maize. A basic solution will make the indigestible skin slide right off the kernel and that makes it way easier to grind corn into a paste.

The solution also gels the corn and yields a more viscous, doughy paste that you can form into tortillas, even though there's no gluten in corn like you have in wheat. The alkaline treatment also deactivates these mycotoxins that are produced by common molds found on corn, and it also makes the niacin in corn bioavailable — an essential nutrient, a B vitamin. If you don't eat it, you get pellagra. So, societies or villages or communities that did this alkaline treatment on their corn, well they would've outlasted the other ones. Nixtamalization, this process is called, and wood ash may have played a role in the historical development of the process, but that's not the whole story, because you can also make a basic solution with rocks and other minerals that you can just pick up off the ground. How people figured that out is another story that we're going to tell another day. Rocks depend on your local geology, but everybody everywhere uses fire. Fire makes ash and ash is going to mix with water all kinds of ways — in the pot or on the ground in a little pool or a pond where you dump your ashes.

People might have noticed that that super ashy water was totally inhospitable to life. Like, no animals, no plants, no algae — nothing could grow in such basic water, and so maybe that's why it might have occurred to some of them to try preserving food in that water. And that's one way we might have gotten century eggs, or lutefisk, or lye-cured olives. You try preserving your olives in lye, and you notice that the lye breaks down the bitter compounds in olives a whole lot faster than brine does, and you notice it keeps them green. Or maybe that's not how we got lye-cured olives, or lutefisk, or century eggs. The world is a complex place and people simultaneously invent things in all kinds of totally different ways, it's not one thing. But I'm willing to bet you that at least some people invented cooking with bases when some ash just accidentally got into the pot, because that's a thing that was simply going to happen...