Tags: Batch 4
Distillation is a fairly simple concept: you heat a liquid containing alcohol (bourbon whiskey mash, for example) and collect the steam. Alcohol has a lower boiling point than water, so it changes phase from liquid to gas at a lower temperature. After the liquid converts to steam, we refine it by giving it several chances to condense: we take heat out, and the substances that require more heat to remain vapor (water) turn to liquid and drip down, while the substances that take less heat to stay vapor (ethanol) do not. Eventually, we cool whatever doesn’t take these opportunities to condense, and collect the resulting liquid.
Fermentation is also fairly simple. It looks something like this:
In an ideal world, it would be a perfect process. The little yeastlies would eat sugar, use the energy, exhale carbon dioxide, and spit out ethanol. We would be left with water, some heat, and ethanol. In an ideal world, I would have gotten a pony for my birthday. We do not live in an ideal world. Fermentation occurs with unwanted side products, and I drive a car to work.
The side products come in all sorts of crazy shapes and sizes. Some of them are delightfully aromatic and full of flavor; most of them are not. Fortunately, they all come with their own special boiling point, so they can be easily separated out from the ethanol and water. We give them two names: heads – for things with low boiling points, like ether and acetone, which come out first; and tails, or feints – for things with higher boiling points, such as fusel oils, which come out after the ethanol (and mixed with the alcohol that doesn’t make it out on its own). The heads are junk, but the tails are full of flavor (and the aforementioned alcohol) and can be further refined.
We use a processing method known as batch distillation; that is, we do one batch at a time, unlike most large-scale commercial distilleries, which use continuous distillation (a post for a different time). In this way, we are able to very precisely separate out the various distillates. There are a number of ways to go about this, depending on the still. Our still is a hybrid pot/column still, which allows for a high level of refinement in a single run – it’s capable of separating out the hearts from the heads and (most of the) tails in a single run. This is as opposed to doing one or more runs – stripping runs – to gradually refine the mash a little more each time before the final (spirit) run.
Allow the following, finely-crafted Paint diagram to demonstrate:
Since we purify out the bulk of the ethanol the first time it goes through, we retain a lot of flavor without having to include any harsher flavor elements. It’s a one-way ticket to Smooth City (yeah, that’s right. You read that correctly. Smooth City. It’s right next to Flavor Town). Likewise, since we do include the tails from one batch to the next, there’s a little bit of all the bourbon we’ve ever made included in each successive run. It requires a little extra work – adjustments need to be made while the still is running to make sure everything is separating properly – but the results are worth it.
On that note, we just finished batch 4; contents were as follows:
Corn – 900 lbs.
Rye – 300 lbs.
Malted rye – 100 lbs.
Malted barley – 300 lbs.
Another double batch, with the same mash bill as batch 3.
If you’re looking for something to do in order to look busy this morning, please feel free to make a better diagram for me. Maybe something with animation and/or glitter.