So far we've gone through almost all of the chemical leaveners that bakers have used to bubble their bread over the ages, and found that the thing they all have in common is that they are alkalines (bases). There is one obscure one I have yet to cover, but I'm wondering first if anyone can guess what it is. If you have any recollection of junior high chemistry class you might be able figure it out. I remember being given little pH test strips for a homework assignment once. I ran all around the house testing every liquid I could find for either acidity or alkalinity. The big takeaway I got from that assignment was that there are far more acids in a typical household than bases. In fact, other than bleach and milk of magnesia, I could only find one. Anyone else remember what that liquid was?

Alright, I'll tell you: ammonia. Noxious, poisonous ammonia. But would you believe that there's a leavening agent that's based (no pun intended) on ammonia, or rather, it's bicarbonate salt? If you're German or Scandinavian you've probably heard of it: hartshorn, a.k.a. baker's ammonia, ammonium carbonate, ammonium bicarbonate or even "salt of hartshorn". It gets its name from deer antlers (literally a male deer or "hart"'s horn) which were in fact the original source for the stuff. These days it's industrially produced.

The thing about baker's ammonia is that it really does make your kitchen smell of ammonia. But if you're using it right all the ammonia evaporates out, leaving nothing but the end product behind. You can't use it as you would baking powder in say, biscuits, but in the right context it can be quite useful (and delicious).

I'm speaking specifically about very thin, very crispy cookies from which the ammonia can easily evaporate. German springerle and/or Scandinavian ginger cookies for example, which owe part of their flavor to the shade of ammonia that the hartshorn leaves behind. I know, it sounds disgusting — but don't knock it until you've tried it!

This is a question that comes up a lot. More than a few quick bread, cake and pancake recipes call for both. The reason, because the acids and alkalines in a leavening reaction must always be balanced. If they aren't, the leftover chemicals create off flavors.

Let's say for example that you're making pancakes and the recipe calls for a cup of flour, an egg, and a cup of buttermilk (instead of milk). If you add a teaspoon of baking powder as a leavener, some of the lactic acid from the buttermilk will react with some of the sodium bicarbonate in the baking powder. You'll get the bubbles you want, but the upshot will be that some of the acid salts from the baking powder (the calcium phosphate and/or sodium aluminum sulphate) will be left over (since they didn't have an alkaline parter to react with). Those unreacted acids salts don't taste very good, and so will give your pancakes a chemical aftertaste. To prevent that from happening you use only 1/2 a teaspoon of baking powder supplemented with a 1/4 teaspoon of plain baking soda.

I know what you're thinking: why not just use all soda and dispense with the baking powder altogether? The answer is because to get the same leavening pop you get from a cup of buttermilk, 1/2 a teaspoon of baking powder and a 1/4 teaspoon of baking soda, you'd need 1/2 a teaspoon of baking soda plus TWO cups of buttermilk, and that would give you the world's runniest batter. Make sense?

Of course alkaline leftovers are just as undesirable as acid ones, for reasons previously discussed. Aside from just tasting funky, alkalines (even weak ones like sodium bicarbonate) combine with fats like oil and butter to create soap, which is a very poor match to maple syrup.

So this is why you find various combinations of soda and baking powder in baking recipes, especially where you have acidic ingredients like lemon juice, buttermilk, molasses, puréed pumpkin and (un-dutched) cocoa powder. It's all about making sure the various leavening agents have chemical parters to react with so that they break down and don't interfere with flavor.

Of course if you are the sort that's put off by aluminum salts, you can always do things the old fashioned way and make your own baking powder. Simply add 1/4 teaspoon of baking soda and 1/2 a teaspoon of cream of tartar for every teaspoon of baking powder your recipe calls for. Best to add them in separately, since it would be a shame if they were to start reacting prematurely. You can make your own storable version of Bird's baking powder by adding another 1/4 teaspoon of cornstarch and mixing it all together. But unless you really need it for say, a camping trip, it doesn't make much sense to risk a premature reaction by combining the soda and tartar ahead of time.

As a general rule, you need one teaspoon of baking powder to raise a mixture of one cup of flour, a cup of milk and an egg.

...was developed by a fellow by the name of Eben Norton Horsford, a student of the world-renowned German chemist Justus Von Liebig. Liebig himself experimented with chemical leaveners, notably by combining sodium bicarbonate with hydrochloric acid, a line of experimentation he gave up when he discovered there was a limited market for leavening reactions that blew a hole in your roof. Horsford's formula by comparison employed calcium phosphate (combined with bicarbonate of soda), which was not only far less expensive than Alfred Bird's cream of tartar version, it was much more dependable (and it also didn't explode). His product, which was named for an esoteric yet fascinating character from American History, went on the market around 1856. It was originally named "Horsford’s Cream of Tartar Substitute" as there was something of a "frankenfoods" scare at the time, and cream of tartar was thought to be bad for you. Nice to know some things never change.

So it's the mid-1800's. Carbon dioxide-producing alkalines are in common use in the baking world, as is cream of tartar as an acid. Why not get nuts, put the two together, and sell the whole shebang as a do-it-yourself one-scoop leavening reaction in a box?

That was the inspiration of one Alfred Bird, a pharmacist from Birmingham. Saddled with a spouse allergic to both yeast and eggs, but blessed with a talent for invention, Bird invented the precursor to modern baking powder in 1843. It was, quite simply, a mixture of baking soda, cream of tartar and cornstarch (which served to keep the reactants separated as well absorb moisture from the air).

The problem with Bird's miracle-in-a-jar was that it was expensive. Cream of tartar didn't come cheaply in those days, and that prevented Bird's powder from being widely marketed. It was however a godsend for those with dietary restrictions, as well as for the English military, for whom it provided "quick breads" in the field.

JP: I'll take organic chemistry for $800, Alex.

AT: An organic acid salt, this by-product of the winemaking process will also help raise your biscuits.

JP: What is cream of tartar?

AT: Correct!

(CHEERS)

JP: I'll take organic chemistry for $1000.

AT: Created under photochemical conditions, this is what results when 1,4-dimethylcyclohexane reacts with an equal number of moles of chlorine gas.

JP: Um...are you freakin' kidding me?

Sure, you can spend your entire baking life making bubbles by mixing soda with acidic substances like buttermilk or sour cream. More than a few of our ancestors did. The trouble with that approach is it's inconsistent. The weather might change and acid-producing bacteria in your clabber jar might stop growing or even go dormant. Or you might just run out. The solution? Ready-made, easily storable acid powder, the thing we know in America as cream of tartar. A little of that mixed into your baking soda batter and you get the very same reaction, every time.

Cream of tartar is something that's been around since antiquity. Known as either tartar or argol, it was nothing more than the crystalline residue left on the inside of wine casks after fermentation. If you've ever opened a bottle of wine and noticed little sparkly bits on the end of the cork, that's it. Scraped off and ground to a powder, it was used throughout the ages as a medicine (a laxative, mostly). Boiled, dissolved, filtered and refined into a white powder, it became tartaric acid or potassium bitartrate, a baker's best friend.

However biscuits are just the beginning of tartaric acid's utility. It can be added to candy syrups to keep them from crystallizing. It helps stabilize whipped egg foams. In cooking it helps keep boiled vegetables green. Around the house you can dilute it in water to clean copper pans or old coins. Combined with a little vinegar it's a great stove top cleaner. Oh crikey will you listen to me? A little caffeine and suddenly I'm Martha Stewart!

Oh well, I've gone this far. Combine a cup of baking soda with a quarter cup of cream of tarter and a cup of salt and you've got a pipe-friendly homemade drain opener (the bubbling action can clear out minor blockages). It's also great for removing rust stains from carpet and bathroom fixtures.

What?

Most days it's a fair bet that should the biscuit bug strike, I won't have any buttermilk hanging around in the fridge (and if I do, it's usually been hanging around if you follow me). Happily, you don't really need store-bought buttermilk to make buttermilk biscuits. As I mentioned, there is no real buttermilk around anymore. What you find today in supermarket refrigerators is skim (or whole) milk that's been spiked with lactic acid bacteria (so-called "cultured" buttermilk). That culture causes the proteins present in the milk to gel a bit, making it a little thicker than regular milk, and of course adds the acid, which is the really necessary bit.

Given that the thickness isn't at all important for baking, and it's really just plain milk anyway, there's no reason you can't just add a little acid to a cup of regular milk and be done with it. Truly. A tablespoon of vinegar will do the trick about perfectly. That or a tablespoon of fresh lemon juice or two teaspoons of cream of tartar. Let it sit for two minutes and bingo: instant home-made clabber. Of course you can also just swap out your buttermilk for an equal amount of plain yogurt since it's pretty much the same thing, but it wouldn't give you the same mad scientist buzz, now would it?

I confess I got a little ahead of myself yesterday bringing up the subject of baking powder. For when last we left the History of Chemical leavening narrative, I was blabbering about saleratus (potassium bicarbonate), which was not in fact the direct precursor to baking powder. That distinction belongs to another compound we all know and love: sodium bicarbonate, also known as baking soda.

Interestingly, sodium bicarbonate was also known "saleratus" for a time. The world's first commercial producer of baking soda, a fellow by the name of John Dwight, originally marketed his product as "Dwight's Saleratus" in 1847. His original trademark was a cow, since sour milk (clabber) was required to activate it. In time (by about oh say 1867) that logo would change to an illustration of a muscular arm hoisting an iron hammer, and well, not much more needs to be said about that (though did you know that a fellow by the name of Armand Hammer attempted to buy Church & Dwight, the makers of Arm & Hammer baking soda in the 1980's? Strange but true.).

But where was I? Oh yes, saleratus (potassium bicarbonate) and saleratus (sodium bicarbonate). It's easy to see how those terms came to be conflated. Both are naturally occurring compounds, though truth be told sodium bicarbonate is much much more common geologically. I mentioned previously that settlers heading west occasionally stumbled across small saleratus deposits (making potassium carbonate arguably the world's first drive-though grocery). The same thing happened with sodium bicarbonate deposits, only where natural potassium bicarbonate might occur over an area of a few square acres, natural sodium bicarbonate would cover the landscape for several square miles.

These huge deposits, discovered in Wyoming, were termed "soda lakes" or "soda beds", and were blanketed by powdered soda to such an extent that it appeared to the pioneers that snow drifts had accumulated in summer. Where did/does the soda come from? The answer: from water. More specifically, water that has flowed over (or through) naturally occurring sodium deposits and collected in still pools. When the sodium molecules in the water come into contact with atmospheric carbon dioxide, they react to form sodium carbonate and/or bicarbonate, which then precipitates out as a powder. Neato.

Eventual settlers in the area (especially Mormons) would come from hundreds of miles away to collect soda from these dry lakes, using it not only as a leavening agent, but for lye and soap making. Of course what the early settlers harvested was but a drop in the bucket in terms of the total deposits in Wyoming, which the St. Louis Globe-Democrat described this way in 1898:

[Wyoming has] enough natural soda in their soda lakes to make all the soda biscuits of the world for the next two centuries, and then throw in, for good measure, sufficient [soap] soda and soda lye to cleanse all the "tribes of earth"...and still have plenty left to make window glass for generations to come.

Hey, I said it was descriptive, not politically correct. To this day Wyoming is one of the leading global sources of so-called soda ash, a raw material derived from a mineral called trona. Some fifteen million tons of soda are produced in the US each year, for indeed it is one of the most important commodities on Earth, used not only to make baking soda, but soaps and detergents and especially glass (see previous posts on potash). So pervasive is its use that soda ash production statistics are one of the measures that researchers use it evaluate the performance of the US economy.

And you thought all there was to soda was a little orange box!

...is that clabber girl. Behind is the family, mama and next-eldest daughter plucking a goose, while the younger kids (and cat) play in the feather box. And while I'm not totally sure, I believe that black earthenware pot just behind the little boy's head (the thing with the spoon handle sticking out) is supposed to be the clabber pitcher. This is an item that was once a fixture in American kitchens prior to about 1900, the vessel in which leftover milk and/or buttermilk was left to "clabber" until it was sour enough to bake with.

Clabber is/was nothing more or less than sour milk, either left out to be slowly soured by lactic acid-producing bacteria, or soured (curdled) rapidly by the addition of some sort of kitchen acid. Vinegar, sometimes, or a rennet of the kind used to congeal cream into curds and whey. Depending on how clabber was made and how it was treated, it could assume any one of several textures. It could be thick and spoonable, it could be a soupy, lumpy consistency, or it could be firm and dry, almost like a cheese. Mostly it was a way to turn something that would otherwise go to waste (excess milk) into something useful.

Clabber came to America by way of the Scots-Irish: back-country Scottish lowland folk who were relocated to Northern Ireland (Ulster) by the English crown, then ultimately emigrated to the New World. The poorest of the poor of our early forebears, they could afford to waste nothing. Indeed, while the English slopped their hogs with the clumpy, curdled milk that remained after their cream was skimmed off, their Northern cousins would just as soon eat it. Protein is protein, after all, especially if you're dirt poor (and Scottish). And so, just as clabber was synonymous with poverty in the old country, so too it was in America, common to Appalachian hill folk and Southern farmers especially, who would slather it over corn bread or just eat it by the spoonful.

As home bakers in America began experimenting with chemical leaveners in the late 18th and early 19th centuries, clabber became useful in another way: as an acid food to combine with saleratus, soda or pearlash to make bubbles in batters and doughs. While the alkaline side of the reaction was typically store-bought, the clabber was always home-made, which while it sounds charming to us, resulted in highly variable and unpredictable leavening reactions. No wonder then that so many home bakers were so relieved to have a consistent leavener like baking powder replace the old soda-and-clabber or pearlash-and-clabber combos. No wonder also why one of the most widely marketed baking powders was (and is) named Clabber Girl.

And with that Paul Harvey-esque finale I'll bring this post to an end.

So far I've limited the chemical leavening discussion to the alkaline side of the equa— er...reaction. Generally speaking though, it takes two to tango where chemical leavening is concerned: an edible CO2-releasing alkaline (of which there are very few in nature) and an edible acid. Put the two together and the result is typically some sort of salt, plus water and the all-important carbon dioxide gas.

Here it's important to note that heat also plays an important role in chemical leavening, since temperatures above about 200 degrees also cause both potassium bicarbonate (saleratus) and sodium bicarbonate (baking soda) to break down, or "thermally decompose" into carbon dioxide gas (among other things). However it's by combining both the acid and the heat that the greatest carbon dioxide "pop" is achieved.

So what types of acids are there in the kitchen that can be used to start such a reaction? Quite a few nowadays. A typical kitchen (on a good day) will contain vinegar, cream of tartar, buttermilk, sour cream, yogurt, citrus juices (especially lemon juice), molasses, cocoa powder, honey and brown sugar — all of which are acidic to varying degrees and can be used in just about any combination to create a leavening reaction. However a home baker in the early nineteenth century likely wouldn't have had access to most of these, she (since let's face it, women did almost all the cooking back then) would have mostly had the dairy ingredients to choose from. However the one that early American bakers gravitated to the most doesn't appear on the aforementioned list: clabber.

Just what is clabber and why was it so popular for baking? More on that a bit later in the day.

An interim step between pearlash and the baking soda and powder we know today was "saleratus", or potassium bicarbonate. I know what you're thinking: a pretty fancy name for an early chemical leavener, what industrial era marketing firm came up with that one? But in fact saleratus is a very old word, Latin in fact, meaning "aerated salt". So the Romans leavened their bread with it? Actually no, however they were aware of it. Potassium bicarbonate is a naturally occurring compound, one that's typically found in dry lake beds. The ancients put it to a variety of uses, though apparently none of them culinary.

Mid-nineteenth century Americans, on the other hand, were all too happy to try it out as a bread leavener. Industrially saleratus was made by combining pearlash with carbonic acid. However pioneers heading west did manage to stumble across naturally-occurring deposits of it from time to time (Saleratus Lake, Wyoming was one such place). Like pearlash, saleratus was entirely functional as a bread leavener. However being another rather strong alkaline, it did tend to create soapy flavors in the presence of fat. It too had to be combined with an acid in order for it to work, and like pearlash worked best with breads that were baked up quickly over high heat.

Of course the world's first chemical leavener wasn't perfect. Sure it made bubbles in batters, yes it was perfectly harmless to ingest. Yet depending on the purpose you applied it to, it could taste, well...nasty. This was especially true if the batter you were intending to raise had any significant amount of fat in it. As I mentioned in the last post: pearlash + fat = saponification (i.e. soap), a most unwelcome thing to have with your morning biscuit and coffee. Thus pearlash, while it was an interesting novelty, was a product without a future. If this type of quick leavening was to be truly useful to the home baker, some sort of alternate chemistry would have to be found.

It wasn't long after Signori Campanella isolated potassium carbonate that enterprising industrialists of the day took the further refining step of heating potash to burn away its ashy residues. This had the effect of turning the powder a sparkling white, which thence became know as "pearl"-ash (strikingly good marketing considering the time).

The main use for this material, as mentioned, was for glass-making. Yet being such a strong alkaline, it was also great for making soap (alkaline + fat = saponification which...oh hell more on that later). Just how it was discovered (and by whom) that pearlash could be used as a leavening agent is something of a mystery. Though it goes without saying that there was an awful lot of enthusiasm for progress in those early industrial days. People were trying all sorts of things. Evidently, somebody somewhere figured out that if you combined pearlash with an acid in the presence of water the result was effervescence (i.e. the release of gas from a liquid solution, in this case carbon dioxide). Hey! Why not put it in bread?

Why not indeed? And many people did just that here in America, the land where, blessedly, people will try just about any crazy idea. And well, it caught on. Exactly when and where again isn't known, however the first recipe ever to call for pearlash was published in 1796 by one Amelia Simmons (it was for gingerbread). Given that Ms. Simmons likely wouldn't have published a recipe that contained an ingredient that wasn't readily at hand, it's probably safe to assume that pearlash was already in wide use in North America by that time. The age of chemical leavening had begun.

Well, er...no. Or at least probably not. Adding a powder that must have tasted like soot to a cake batter probably wasn't every settler's way of celebrating his birthday. Most of the time the potash was refined a bit more, a step I'll describe in a moment. However before I do it's interesting to point out that there is evidence to show that Native Americans were making use of chemical leavening well before European immigrants ever thought to employ it. Which is to say they were known to add ashes to their corn cakes to lighten their texture. These (still mostly flat) ashen-tasting flapjacks (called nokechick) were a horror to wheat-loving European settlers or the time. Yet they do seem to show that while Native Americans weren't privy to the discoveries of Antonio Campanella, they did by trial and error discover an alkaline's ability to alter the texture of bread.

Joe, when you say chemical leavening started with potash, do you mean the same potash I buy in bags at the hardware store to use in my garden? Yes that's right, the very same stuff. Being such a strong alkaline, it is also extremely useful in neutralizing acid soils.

One could make the argument that the age of chemical leavening began when potassium carbonate was first isolated and definitively identified by chemist Antonio Campanella in 1745. Potassium carbonate is the principal component of potash, which was by far the most important chemical compound in (and one of the chief exports of) colonial North America.

But then what the heck is potash and why was it so important? Potash, as its name implies, derives from wood ashes. It's an alkaline substance that was (and still is) extremely important to the manufacture of glass. Why is that? Well we all know that glass is made by melting down sand (silica) and manipulating it into various shapes. It takes a lot of heat to so that. In fact pure silica has a melting point in excess of 3500 degrees Fahrenheit. A fire that hot, especially for glass makers of old, was very difficult to create, and almost impossible to work around. But what if you could add something to the silica to lower its melting point and make the work environment more tolerable? Substances like these, which when combined with other substances lower their melting points, are known as fluxes in the chemical world. That's what potash was: an additive that lowered the melting point of silica by about 1700 degrees. Much better.

The trouble was that potash was in short supply in the Old World, due to a distinct lack of trees. All that changed of course when the New World, and its seemingly endless forests, was discovered. North America became a veritable potash factory as settlers began to occupy tracts of land and clear-cut the old growth trees, which were especially rich sources of the stuff. Cut down and burned for their ashes, they provided a cash infusion that immigrant farmers desperately needed to buy seed, supplies, and building materials for their homes.

But then how is potash made? Basically, by putting wood ashes into a vessel with a hole at the bottom and soaking them with water. With time the water leeches the impure potassium carbonate out of the ashes, and it drips out the bottom of the vessel. Anyone know what this liquid is called? Anyone? Anyone? Yes you at the back with the chemical burns. Yes that's right: lye. Lye is a caustic alkaline liquid that had a variety of uses back in the day. Dried, however, it yielded a black powder: potash.

It took over an acre of big, old-growth trees to produce a single ton of potash, but then the early colonists weren't really thinking about that. From their vantage point the forests of North America went on forever. And oh boy were the glass makers of the Old World willing to pay for the stuff. Potash was, as I mentioned, one of the central pillars of the early American economy. No wonder then that the very first U.S. patent ever issued went to a gentleman by the name of Samuel Hopkins of Philadelphia for an improved method of "making pot ash and pearl ashes" in 1790. Of course potash was just as important to Canada, which remains the world's leading producer of potash to this day.

The first of the "Big Three" leavening methods is chemical leavening. It's the latest of the three to arrive on the baking scene, having been invented right about the time of the First Industrial Revolution, some 230 years ago. As its name implies, it involves using chemicals to create "seed" bubbles (usually of carbon dioxide) in wet doughs or batters. I say "seed" bubbles because just as with microbes, chemical leaveners can only push a bread up so far. They can initiate the process certainly, but the real heavy lifting is done by steam. And if that sounds like mechanical leavening to you, it's a because it is. Mechanical (or steam) leavening is part of every leavening method. Whether alone or teamed with others, it is the true engine of bakery.