A Three-Minute Guide To Fermentation And Distillation
Whether beer, wine, or spirits are your jam, knowing how your drink of choice is made is the first step to becoming an expert consumer. Although we tend to get caught up in the minutiae of aging regimens, tasting notes, and other minor details, bringing it back to the basics – that is, knowing how our base alcohols are made – is essential.
The first step is understanding the differences between alcohol-producing processes: fermentation and distillation. While wine and cider are made from fermented fruit, beer and spirits are made from fermented cereals, such as barley, rye, or other base grains. Distillation is what sets spirits apart from beer, as these heavy-hitters undergo an additional process before being aged and bottled.
So what exactly are the differences between fermentation and distillation? Look no further than our quick and easy-to-digest explainer, here.
Simply put, fermentation is a metabolic process in which substances are broken down into simpler matter. In addition to beer, wine, and spirits, other consumable items such as bread, kimchi, and yogurt also undergo fermentation.
In the fermentation of fruit for wine and cider, glucose is chemically broken down via microorganisms (yeast) and is converted into carbon dioxide and ethyl alcohol. Heat is also a byproduct of fermentation.
This process of fermenting fruit has existed for over 10,000 years and has been used throughout various cultures. Basically, anything with sugar can be fermented and converted into alcohol, though in the case of wine and cider, grapes and apples (respectively) are the most common.
Fermentation of grapes is often done in stainless steel tanks, concrete vats, or various wooden vessels (barrels, barriques, tonneaux, etc.) Producers must also choose between using ambient yeasts, which are naturally present in cellars/vineyards, or cultured yeasts, which are isolated and added. Ambient yeasts, which are often referred to as wild yeasts or native yeasts, tend to lead to longer fermentation times and uniquely ‘terroir-reflective,’ flavors.
There are hundreds of cultured yeasts available for winemakers to purchase and use, each of which brings a different flavors and characteristics to a given wine. It’s this debate over terroir reflection that tends to divide winemakers on the topic of native vs. cultured yeasts. Once a winery or cidery has been in existence for a decent period of time, an ambient ‘house yeast’ can begin to form.
Wines and ciders become fermented ‘dry’ when yeasts (ambient or cultured) consume all of the sugar present in the juice. Yeasts also cannot survive past a 15 per cent ABV; if there are still sugars present in the juice, this is how certain wines (think Port, VDNs, etc.) though not all wines become sweet.
Basic steps for wine-making
Note that there are many other decisions that go into the below five steps. This is simply the most basic five-step break down to understanding the grape to bottle process.
1 – Harvest
2 – Crush/press fruit
3 – Fermentation (Juice → Wine)
4 – Age
5 – Bottle
Other popular forms of fermentation are bottle fermentation, carbonic maceration, and malolactic fermentation. Bottle fermentation is the process in which Champagne (and some other forms of sparkling wine) get there fizz. In short, a base wine is made and bottled, then a liqueur de tirage (combination of sugar and yeast) is added to the bottle to re-ignite a second fermentation.
Since carbon dioxide is a byproduct of fermentation, this secondary fermentation allows for trapped CO2 to create the fizzy bubbles we all know and love in Champagne.
Carbonic maceration is a process in which fermentation takes place inside of whole (not crushed) grape berries. This happens by placing grape clusters in a closed container and replacing the oxygen with carbon dioxide. Enzymes within the grape are broken down and converted into alcohol, then the grapes are crushed and normal fermentation takes place.
These wines are often light-bodied, easy-drinking, and have tons of fruit-forwardness. Malolactic fermentation is the process in which bacteria rather than yeast converts malic acid into lactic acid. Malic acid tends to be tart and lip-puckering; this process converts these acids into lactic acids, which lead to softer, creamier, and smoother final wines.
Understanding how grain-based spirits are made seems complicated, but it’s actually rather simple. Depending on the whisky, grains (barley, rye, or something else) are moistened and allowed to sprout. This germination process is called malting, and the point of it is to convert starch to sugar. The process is cut off by dry heating the grains.
Now that we have sugars, said sugars must be extracted to be fermented. This is done through mashing, which incorporates putting ground up grains into a vessel with hot water. The oatmeal-like substance that is produced from this is called mash or wort (the latter if solids are strained out of it). Next comes fermentation, then distillation.
Distillation is the process in which alcohol levels of a given liquid are increased. This is done through stills, the most popular two types of which are called pot stills and column stills. The former are generally used to make whiskies worldwide and is considered a ‘batch process.’ Certain whiskies will even undergo two or three distillations before aging.
Distillation incorporates heating up the substance, and since alcohol boils at a lower temperature than water, allows these two to separate. The alcohol will evaporate off of the liquid, condense, and then be turned into liquid again. The spirit will then go into a second or third still, where this process is repeated. Each time that the process is repeated, the final ABV increases. The distiller cuts the spirit (known as the spirit’s ‘head’ and ‘tail’) to get rid of unwanted flavors and aromas. What’s left is known as the heart. This is what goes into barrels and ages.
Column stills, sometimes referred to as continuous stills, are more commonly used in the process for making bourbon, rye, and other whiskies. Column stills (as the second name implies) work continuously, meaning that the distiller puts the liquid into the top of the still and is passed through a series of plates. The steam rises and separates out the solids, pushing alcohol vapors up. Each plate condenses the vapor and increases the alcohol content.
Whether pot or column stills are used, both distillation vessels leave the producer with a final ‘heart’ (spirit), which the distiller then decides in which type of vessel and for how long to age it for.
Basic steps for distillation
Like with the fermentation process, note that there are many other decisions that go into these six steps for distillation. This is simply the most basic six-step break down to understanding the grains to bottle process.
1 – Malting
2 – Mashing
3 – Fermentation (Grains → Alcohol)
4 – Distillation
5 – Aging
6 – Bottling
(Lead image: Maksym Kaharlytskyi / Unsplash)
Published 23 December, 2019