Distilling 101, Part 2: Making the Wash

In our first Introduction to Distilling article, we explored what distillation is, some of the different spirits produced around the world, and the major pieces of equipment used by distillers.  This time, we’re going to back up a bit.  Before anything reaches a still, somebody has to make the alcohol.

For beer brewers, that part of the process should look surprisingly familiar.  A grain spirit begins with grain, water, enzymes, and yeast.  We need to make starch accessible, convert it into fermentable sugars, give healthy yeast an appropriate environment, and allow fermentation to produce alcohol.  The result is commonly called a wash.  If you’ve been following our Homebrew Skills Tree, you’ve already learned most of the science involved.  Milling, enzymes, water chemistry, oxygen, nutrients, gravity, yeast health, and temperature control all come back into play.  So let’s walk through a distiller’s brew day—from grain to a finished fermented wash.

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A Quick Legal Note: Federal law allows qualifying amounts of beer and wine to be produced at home for personal or family use, but there is currently no equivalent federal personal-use exemption for distilled spirits.  Beverage distilled spirits must be produced at a federally qualified distilled spirits plant (DSP), and a DSP cannot be located in a residence or in certain connected premises.  State and local requirements may apply as well.

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Mash, Wort, or Wash?

You’ll hear all three words in distilling conversations.  The mash is the mixture of grain and water where starch is made accessible and enzymes convert it into sugars.  The sugar-bearing liquid produced from that process can reasonably be called wort, particularly for those of us coming from brewing beer.  Once yeast ferments it, wash is commonly used for the alcoholic material intended for distillation.  With grain fermentations, you may also hear terms such as distiller’s beer.

The important progression is:  Grain → starch → sugar → fermentation → wash.  The still is missing from that sequence?  The still doesn’t make the alcohol .. the yeast did!

Let’s Start With Corn

Suppose our eventual goal is an American-style corn-based whiskey.  The first misconception to eliminate is that corn is “high in sugar.”  It really isn’t, not in the sense that honey, grape juice, or apple juice is.  A kernel of corn stores much of its energy as starch. Yeast cannot efficiently ferment that starch directly.  We first need to break it down into smaller sugars that yeast can metabolize.  That’s why a distiller’s brew day begins much like an all-grain beer brew day.  We need to expose the starch, make it accessible, and give enzymes the opportunity to break it apart.

Does the Corn Need to Be Crushed?

Yes.  Think back to our grain-milling article. An intact kernel is an excellent little biological storage container. That’s exactly what the plant designed it to be.  Unfortunately, we’re trying to get inside.  Milling cracks the grain, increases its surface area, and gives water and enzymes much better access to the starch.  That doesn’t necessarily mean turning the corn into flour.  Extremely fine grain can become difficult to mix and handle.  But whole kernels dramatically restrict access to what we’re trying to convert.  Commercial distilling processes vary considerably, but the principle remains:

Open the grain so water, heat and enzymes can reach the starch.

Some modern distilling products even support processes using uncooked grain.  For example, Angel’s Yellow Label product combines microorganisms and enzymes in a process designed specifically for starch-based raw materials.  That’s a very different approach from the traditional cook-and-mash process we’re discussing here, but the underlying requirement remains the same: somehow, that starch has to become fermentable sugar.

Corn Has Another Trick: Gelatinization

This is where a beer brewer encounters something new.  Malted barley behaves conveniently at familiar mash temperatures.  Raw corn doesn’t.  Corn starch is stored in granules.  When those granules are heated in water through their gelatinization range, they swell and lose their organized structure.  The starch becomes much more accessible to enzymes.  If you’ve ever cooked grits or polenta and watched the mixture thicken dramatically, you’ve seen starch gelatinization happening in your kitchen.  For a conventional raw-corn process, that means we generally need considerably more heat than a normal barley mash before ordinary saccharification can efficiently proceed.  There’s also an important distinction at the homebrew store:

Raw corn isn’t the same thing as flaked corn.

Flaked maize has already undergone heat processing that gelatinizes its starch.  That’s why beer brewers can generally put flaked corn directly into a conventional mash with malted grain.  Ingredient selection can therefore change the entire brew day.

Now We Need Enzymes

Accessible starch still isn’t yeast food.  We need enzymes.  Malted barley naturally provides amylase enzymes, which is one reason it has been so valuable to brewers and distillers for centuries.  Alpha-amylase attacks large starch molecules internally, chopping them into shorter chains and helping liquefy the thick mixture created by cooked grain.  Beta-amylase, naturally present in malt, works differently, producing significant amounts of maltose from those starch chains.  Modern distillers can supplement or replace the enzymes supplied by malt with commercial enzyme preparations.  Glucoamylase, for example, can continue breaking dextrins toward highly fermentable glucose.  This is where the goals of brewing and distilling begin to diverge.  A beer brewer may intentionally leave some dextrins behind because they contribute body and character to the finished beer.  A distiller generally has much less use for carbohydrate that the yeast can’t ferment.  Unfermented starch or dextrin represents potential alcohol that was never produced.  So wash production commonly emphasizes efficient conversion and high fermentability.

Do I Need Malted Barley?

Not necessarily.  A traditional grain bill can use the enzymes naturally supplied by malted grain.  Modern processes can instead supplement those enzymes with commercial alpha-amylase, glucoamylase and other enzyme preparations.  That gives today’s distiller considerably more flexibility in choosing a grain bill.  Products such as DistilaZyme AA are designed to help liquefy starch in whole-grain distilling mashes, while glucoamylase preparations can continue conversion toward fermentable glucose.  Then there are products such as Angel Yellow Label, which combine fermentation organisms and enzyme activity into a process designed around starch-based raw materials.  These aren’t simply different brands of the same thing.  They represent different approaches to solving the same biological problem:  How do we efficiently turn the starch inside our grain into sugar the yeast can consume?

What Should the Grain Bill Look Like?

Now we reach the artistic side.  Corn, barley, rye, and wheat aren’t simply interchangeable sources of starch.  They also contribute different flavor precursors.  A corn-heavy fermentation creates a different foundation from malted barley.  Rye brings another character, and wheat another.  And, of course, different spirit traditions use different raw materials.  Whiskey may begin with grain.  Brandy begins with fruit.  Rum begins with sugarcane products.  Other spirits begin with agave, rice, molasses, and many other fermentable materials.  The eventual distillation doesn’t make those ingredient choices irrelevant.  Quite the opposite.  The raw materials, fermentation conditions, and yeast all contribute compounds that can influence the character of the finished spirit.

Does Distilling Water Need a Special Profile?

Yes, but we’re thinking about water somewhat differently than we do for beer.  We’re probably not trying to create the sulfate/chloride balance of an IPA or reproduce the water associated with a Czech lager.  But water chemistry still matters because enzymes and yeast care about their environment.  Start with clean, good-tasting water without problematic chlorine or chloramine.  Then pay particular attention to pH.  Enzymes have preferred pH and temperature ranges.  Malt enzymes and commercial enzyme preparations don’t necessarily have identical requirements, so the appropriate conditions depend partly on the conversion method you’re using.  Minerals can also influence enzyme activity and yeast health.  So don’t ignore the water, just recognize that we’re optimizing it primarily for starch conversion and healthy fermentation, rather than trying to make the mineral profile itself a major flavor component of a pint of beer.

How Strong Should We Make the Wash?

Here’s an easy beginner mistake.  If more sugar means more potential alcohol, why not make the strongest possible wort?  Because yeast is alive.  A very high initial sugar concentration creates osmotic stress before fermentation even gets underway.  As  fermentation progresses, increasing ethanol creates another source of stress.  Nutrient limitations and excessive temperatures can make matters worse.  Eventually, chasing additional alcohol can produce slow fermentation, stressed yeast, undesirable  fermentation character or a fermentation that simply stops.  Distilling yeasts are often selected for traits such as alcohol tolerance, temperature tolerance and rapid fermentation.  But “can tolerate more alcohol” doesn’t mean “make the strongest wash possible.”  The objective is a healthy, effective fermentation.

Oxygen Still Matters

Our regular Skills Tree readers already know this one.  During the early growth phase, yeast uses oxygen to help synthesize sterols and unsaturated fatty acids needed for healthy cell membranes and reproduction.  So appropriate oxygen availability at the beginning can help establish a strong fermentation.  Once fermentation is underway, deliberately introducing oxygen is generally no longer our objective.  The destination of this fermentation may be different, but Saccharomyces is still Saccharomyces.

Does a Grain Wash Need Nutrients?

It may.  An all-malt brewer’s wort can provide substantial yeast nutrition.  A corn-heavy or otherwise adjunct-heavy wash isn’t automatically equivalent.  Yeast needs more than sugar.  It needs usable nitrogen, amino acids, vitamins, minerals and trace elements. Zinc, for example, plays important roles in yeast metabolism.  That becomes increasingly important as we push fermentation harder.  This is why manufacturers produce distilling nutrients containing combinations of nitrogen sources, vitamins, minerals, and other compounds intended to support healthy fermentation.  The question isn’t “Do distillers use yeast nutrient?”  It’s “What nutrition does this particular wash already provide, and what is my yeast likely to be missing?”

Choosing the Yeast

This may be one of the most interesting decisions of the entire process.  You could ferment sugar with many strains of Saccharomyces cerevisiae.  They won’t all produce the same wash.  Distilling yeasts can be selected for alcohol tolerance, temperature tolerance, fermentation speed, sugar utilization, and flavor production.  A malt-whiskey yeast might be chosen partly for its ability to ferment the sugars produced by malt and for the congeners it creates.  A grain-whiskey strain may be optimized for corn or wheat fermentation.  Some strains produce relatively clean fermentations, while others produce more esters and higher alcohols that can contribute to the eventual spirit’s character.  That’s why products such as Angel AG-2 are targeted toward grain whiskey, while Angel AM-1 is intended for malt-whiskey applications.  Other strains and manufacturers offer their own combinations of fermentation performance and sensory characteristics.  And Angel Yellow Label is different again because it combines the fermentation culture with enzymes intended to help make starch available during its particular process.  So yeast selection should answer What fermentation performance and flavor profile am I trying to create?

Wait, Doesn’t Distillation Remove All That Flavor Anyway?

No.  This is one of the most important connections between fermentation and distilling.  Yeast produces ethanol, but it also produces esters, aldehydes, higher alcohols, organic acids, and many other flavor and aroma compounds (distillers call these congeners).  Some are desirable.  Some aren’t.  Some can influence later flavor development.  That means the fermented wash establishes part of the chemical palette available to the distiller.  This is why whiskey producers care about yeast strain and fermentation conditions.  Fermentation isn’t merely the factory that supplies ethanol to a still.  Fermentation is part of flavor development.

How Do I Know When the Wash Is Finished?

Exactly the way we’ve learned to evaluate our other fermentations, Measure it!  Take an original gravity reading before fermentation.  Monitor fermentation conditions and gravity as it progresses.  Don’t declare fermentation finished simply because an airlock stopped bubbling.  When gravity has reached its expected endpoint and remains stable, fermentation has done its job.  At that point, we’ve accomplished something very familiar, we converted grain starch into sugar and sugar into alcohol.  What happens beyond the fermented wash belongs to the distilling side of the process.

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Beer Brewer to Distiller Decoder Ring

For an experienced all-grain brewer, that’s a pretty familiar list.

Your First Wash: Putting the Brew Day Together

Once we strip away the unfamiliar terminology, the basic workflow is surprisingly straightforward:

Choose the grain → mill the grain → make its starch accessible → convert the starch with the appropriate enzymes → establish suitable pH and gravity → cool → provide appropriate oxygen and nutrition →
pitch the selected yeast → control fermentation temperature → monitor gravity → allow fermentation to finish.

The exact temperatures, grain preparation, enzyme dosages, pH ranges, and fermentation conditions depend upon the ingredients, enzymes and yeast you’ve chosen.  Follow the technical specifications for those products rather than assuming that one mash schedule works for every grain or every enzyme.  That’s why learning the science first matters.  Once you understand what each step is trying to accomplish, recipes become much easier to understand and troubleshoot.

A Note About Home Distilling

There’s also an important movement underway to change the legal landscape for hobby distillers.  The Hobby Distiller’s Association has advocated for federal treatment of hobby distilling comparable to the exemptions already provided for home beer and wine production.  Its stated goal is legalization of small-scale, personal, noncommercial production rather than unlicensed commercial distilling.  Rick Morris and  the HDA have spent years advocating for that change and working to bring hobby distillers into a clear, responsible legal framework.  North Texas Homebrew Supply supports efforts to establish an appropriate legal framework for responsible hobby distilling, just as generations of homebrewers and winemakers have benefited from laws allowing them to learn and practice their crafts at home.  NTHBS is a proud member supporter of the Hobby Distiller’s Association.

But advocacy for changing the law and the law as it exists today are different things.  Remember, federal law currently provides no personal-use exemption for producing distilled spirits at home.

Learn more about the Hobby Distiller’s Association and its legalization efforts

It Starts With Fermentation

If you’ve been following our Homebrew Skills Tree, you’re not learning a whole new craft here.  You already understand milling, mashing, enzymes, water chemistry, gravity, oxygen, nutrients, yeast health and fermentation temperature.  What changes in wash production is how we apply those skills.  We’re trying to efficiently turn grain starch into fermentable sugar.  We’re choosing yeast not only for fermentation performance but also for the flavor compounds it produces.  And we’re treating the fermented wash as an intermediate product rather than the finished beverage.  Most importantly, we’ve learned something fundamental about distilled spirits:

The still doesn’t make the alcohol. Fermentation does.

The quality and character of a future spirit therefore begin long before anything reaches a still.  They begin with grain, water, enzymes, yeast—and a well-managed fermentation.

Check out NTHBS for all of our distilling-related ingredients and supplies.

Cheers!

-eric-