Alcohol, specifically ethanol, is the stuff we drink. Beer, wine, whiskey, vodka, tequila, schnapps, it doesn't matter. The alcohol itself is all the same.
But where does ethanol come from?
Yeast. Yeast make alcohol. How they do it is pretty amazing.
Yeast are micro-organisms, living things. Like all fungi, they have some plant characteristics and some animal characteristics. Yeast make alcohol through a biological process. Sugar, dissolved in water, is ingested by the yeast organism. The sugar is metabolized, generating energy for the organism's life processes such as reproduction. The waste product it discards consists of alcohols (primarily ethanol) and carbon dioxide.
This process is called fermentation.
Since yeast eat sugar, it is easier to make alcohol from sugar sources (fruit, honey, sugar cane juice) than from starch (grain, potato). Saccharification is the process of converting starch into sugar, thereby making it something yeast can eat. It is a prerequisite for making beer and whiskey.
Grains are seeds. To grow, new sprouts need sugar, just like yeast do. So at the beginning of the germination process the new sprout produces diastatic enzymes that convert the starch surrounding it into sugar. The process of sprouting grain to capture those enzymes is called malting. Any grain can be malted but barley is particularly good. The enzymes produced are so effective that a relatively small amount of malt (about 10%) will convert a mash of unmalted grains.
In Scotland, the law requires that only barley malt be used in the production of whisky. In the United States, enzymes derived from other sources may be used and sometimes are, but most whiskey makers use malt. Some use both.
Enzymes are proteins that promote chemical reactions. All chemical reactions within cells are controlled by enzymes, so enzymes are also involved in the biological process by which yeast make alcohol. You might think that modern science could just synthesize all of these different chemicals and make alcohol in some kind of machine. Maybe it can, but all of the alcohol we drink is still made the old-fashioned way, by feeding sugar to yeast.
All of these processes take place in water so before anything else can happen the starches have to be dissolved. First they are ground to the consistency of corn meal, then water is added. Most starches have to be cooked to fully dissolve. This is especially true of corn, the main ingredient in bourbon whiskey.
Some solids, mostly cellulose, remain undissolved. Most brewers and some distillers discard the solids. Bourbon makers typically do not and they continue through the distillation process. What is left after all of the alcohol has been removed can be used to feed livestock.
Finally, it should be disclosed that I am not a scientist, just a scribbler, but one with a strong interest in most things having to do with the production and consumption of ethanol. It is a subject about which there is great interest and also much misunderstanding. I hope this helps.
CLARIFICATION (1/24/17): In Scotland, the law requires that only barley malt be used in the production of whisky, for saccharification purposes, and for the production of malt whisky. Scotland also produces an enormous amount of grain whiskey for blending, using unmalted wheat, corn, barley, or any other available grain. The enzyme source for that whiskey also must be malted barley, but the rest of the mash can be and usually is unmalted grain.
Chuck, that was such a concise and simple explanation of the process, I think it should be framed! A better explanation I never heard. I vaguely remember chemistry class in about 10th grade having almost a weeks worth of study and discussion about it; but I never learned it as well as this post teaches it. I did get an A in that class; but I have little how I did it. HA!
ReplyDeleteChuck, When we see a 100% rye whiskey, is it correct to assume that all of the rye had been malted? Or is it likely that only some percentage of the rye was malted and the remainder is cooked rye mash, allowing the malted rye enzymes to convert the unmalted grain starches the rest of the way into sugar?
ReplyDeleteI was hoping that you might speak about how the ABV of the distillate is affected by the type of still it is produced on and how a distiller controls the ABV of something coming off of the still (such as to keep it below 160pf).
ReplyDeleteGreat post even without these nuggets.
Hi there,
ReplyDeletehi Chuck. This is a bit misleading "In Scotland, the law requires that only barley malt be used in the production of whisky."
It is true for single malt whisky but for grain whiskies to be used in blends or to be consumed as single grain. Those do not have to be made from malted barley.
Grain whisky used to be made from American corn in the 1960s and 1970s in quite the same way America makes bourbon and these old grains made from corn of today at the age of 40+ years are whiskies. No doubt.
Nowadays the grain component for blended Scotch is made from wheat - the cheapest grain around at the moment.
As with your bourbon malted barley is used to further the change from starch to sugar and to help fermentation.
But not all whisky made in Scotland is made from malted barley alone.
Greetings
kallaskander
Wow Chuck! Much of what I do involves educating people about many aspects of liquor, particularly whiskey. There is often much research involved followed by the acts of compiling the information then boiling it down into something that is concise, meaningful, understandable and usable. You have done a most remarkable job of that here. What would one have to do to get permission to forward this information (with full credit to you) to interested parties?
ReplyDeleteUnless the product claims to be 100% malted rye (e.g., Old Potrero), it probably is not. In the case of MGP's 95% rye, the rye is entirely unmalted and the 5% is barley malt. In the case of a distiller using less than 10% malted grain, there is a good chance that supplementary enzymes are used.
ReplyDeleteExcellent post Chuck!
ReplyDeleteAnd the by far largest producer of 100% rye whiskey, also the source of quite a few "craft rye whiskeys" in the US, Alberta Distillers in Canada, uses no malted rye at all, but pretty much does it all with enzymes.
ReplyDeleteMankind has been utilizing yeast in this fashion for over 5000 years.
ReplyDeleteI think the exogenous enzyme question is an interesting one that should get more attention in the US. As an earlier reader demonstrated, there is a lot of confusion about the nature of so called 100% rye whiskies and 100% corn whiskies. To the layperson, this is an easy enough claim to take at face value. Most people don't know or care about how enzyme makes whisky possible. To the enthusiast with a basic working knowledge, however, this notion runs into some serious cognitive dissonance. "Is some portion of this 100% corn or rye whisky malted? What I understand about the mashing process would demand that it is, so I'll just make that assumption." And why wouldn't they? Industrial fungal amalayse enzyme is simply no part of any narrative that any distillery wants to share with its public. It contradicts the entire mythology of whiskymaking as a heritage, handmade, traditional process. There is an inherent irony in the very nature of MGPs 5% malted barley addition to the 95% rye whisky. It's a token amount included to enable the semi-initiated to assume that the barley malt enzyme is doing the saccrification. But of course it is a healthy dose of industrial enzyme that is doing the heavy lifting.
ReplyDeleteDo I think whiskies using enzyme are bad? Hell no--many are delicious. But I find the nature of the process less interesting, more industrial, and, in comparison to naturally made whiskies, less deserving of being clothed in the mantle of tradition they go to great lengths to be associated with.
Chuck,
ReplyDeleteMy grad work was in oenology and distillation of spirits. You're description is concise and correct.
An interesting aspect of the fermentation process is how aggressive the reaction is. Chemical reactions can be influenced by the presence or absence of products and feed material. Fermentation should be slowed by a build-up of carbon dioxide. I heard that a group of researchers tried this and have up when the test equipment failed at seven thousand atmospheres of pressure.
Chuck,
ReplyDeleteFor a non-scientist you did a great job! When people visit the distillery one of the most common comments when seeing the distillate come out of the still is "That will make you blind!" So I begin the explanation by stating that distillation is a process of SEPARATION not CREATION and that creation happens during fermentation. In addition to making ethanol during fermentation the yeast are also creating methanol, propanol, acetates and some other things. Luckily for us the chemicals vaporize at different temperatures so through distillation we can separate the things we want (ethanol and flavor) from the things we don't (methanol in particular). Methanol (sometimes called wood alcohol) is the chemical that causes blindness and death, but also the thing that causes a headache when you drink. It is in ALL fermented beverages including beer and wine BUT through distillation can be removed.
Not all distillers remove methanol. Methanol is used to "denature" industrial alcohol (ethanol) so that people do not drink it (because no tax has been paid on it).
Yeast are amazing critters. What they do and produce in terms of flavors can be influenced by how they are treated. Things like temperature, food supply and oxygen influence what they do. The goal of whiskey distillation is to get rid of the things we don't want (chemicals and flavors) and keep the ones we do want (ethanol and flavors from the grain and yeast). This is why bourbon may not be distilled above 160 proof. (note whiskey can be distilled up to 190 proof which is essentially flavorless).
Most people do not understand that yeast is in the atmosphere everywhere. If you have ever had fruit spoil it is fermenting (also bacteria). One method of propagation is through spores like mushrooms. The spores are in the air all over the planet. So if you want to start fermenting just set out something with sugars in it and you will get fermentation!
Thanks for the interesting write up!