Archive for the ‘Fermentation’ Category
Posted July 17, 2012 by your friendly neighborhood distillers
Today (technically; it was well after midnight, after all) we finished distilling our second batch.
I say “finished” because so far, we’ve divided both batches into three parts, and combined the distillate after each run – and this was the third part. Our mash tank is 1,800 liters (about 475 gallons) and our still is 600 liters (just under 160 gallons); it’s designed to divide up evenly, and it’s very convenient to do so. In the future we’re certainly going to try 1/3 tank batches, and double-tank batches, and so on – but for now, the three-part batch it is.
In the meantime, we’ve got two batches’ worth of bourbon ready to go into barrels. Technically it’s “whiskey made from bourbon mash” until we put it in charred, new, American white oak containers – so it’ll be bourbon in a few hours. On a side note, it doesn’t matter how long it stays in the container – 20 seconds or 20 years; as soon as it goes in, it’s bourbon. If it’s in there for two years, it becomes straight bourbon, but otherwise there is no age requirement. Of course, if we used a barrel for 20 seconds it would be kind of a waste of a barrel – it would no longer be new so we couldn’t use it for bourbon (or rye, for that matter) anymore, it wouldn’t taste like bourbon, and it would likely impart too strong a wood flavor into whatever came next. But I digress; that’s a topic for a different post.
And let me back up a minute here, to batch one, which we distilled the first week of July – two days after the first post, in fact. Putting it in the still and waiting for it to heat up was both awesome and torturous, and – after we made that first cut (see below) – watching bourbon pour off the spout for the first time was just incredible. Incredible enough to write in bold, because it’s hard to really describe how it felt. Two years of planning, coordinating, setting up, and plain old hard work (plus plenty of red tape) finally paid off. High fives all around. Serious, palm-stinging, ear-piercing high fives.
Anyway. Batch two started off a little different than the first one – we tried using some malted rye in this one, which contains more alpha amylase than malted barley. Remember how much research on beta amylase you did after reading the last blog post? Well, alpha amylase is kind of like beta amylase’s overprotective, slighly lazy bully of a cousin; it softens up the larger starch molecules so beta amylase has an easier time finishing it off. It’s also found in human saliva, which is helpful for making chicha. Don’t worry; I’ll remind you to look that up later. At any rate, whether it was because we are now experts (unlikely) or because of the extra alpha amylase (possible) or because we added the malted grains at the correct temperature instead of being a little on the warm side (pretty good chance), things happened a lot more quickly this time around, and we got much better starch conversion in less than half the time. We also cooled the mash and added the yeast while it was still in the mash tank, so it got mixed in evenly. We ALSO added an ale yeast to the distilling yeast. In short, we don’t know which variable worked, but in addition to the better starch conversion we got a much better attenuation (sugar going from lots to none, thanks to the yeastlies) – which translates into a higher alcohol yield. Hooray!
Once we were satisfied that the yeast had done its best (and was dead), we pumped the fermented mash into the still. Distillation takes about 18 hours on our equipment, from the time we switch it on to the time we switch it off. It’s divided into several parts: warm-up, foreshots, heads, heart, and tails. The warm-up and the foreshots are boring; three hours of watching thermometers creep up and a few drops of especially undesirable compounds come out of the spout. It starts to get slightly more exciting as the little windows on the column begin to show signs of condensation, and then really exciting when the plates start to fill. Since we’re making our product on really efficient equipment, we only need one run through the still to make whiskey; this way, we keep as much flavor as possible, and the cuts are easy to make.
By cuts, I mean one of the (most distinguishing) characteristics of single-batch craft distilling. We make two cuts: heads-to-hearts and hearts-to-tails. The first occurs after the “low wines” – compounds with low boiling points – come through the still. These are things like methanol, ether, and acetone; products of incomplete fermentation, non-starch plant compounds being metabolized, and so on. It’s nasty stuff, but it’s easy to detect and easy to remove (and the worst of it has already come off in the foreshots). It smells and tastes horrible, and when it’s gone it’s quite apparent – really, it’s junk. We’ve got a nice collection of it here…great for sanitizing hoses, starting fires, windshield wiper fluid, etc. Then: the good stuff, or hearts. The hearts run for quite some time: delicious, fresh whiskey pouring out our magical little spout for hours. When the alcohol percentage starts to drop off (the target is 80-55%), it begins to pick up some other flavors and compounds from the other liquids that come through the still with it – most notably, fusel oils and acetic acid. They aren’t harmful, but they don’t smell or taste great at high concentration (and give not-terribly-pleasant hangovers), so we make the second cut – the tails (or “feints” in Scotland). We then let the tails run down to zero (which takes almost as much time as the hearts, and which is on a par for boredom with the warm-up) and save them. There’s still a lot of good alcohol in there, and the complex combination of alcohol, oils, water, and so on mean the tails are full of rich, complex flavors and aromas – so they get mixed in with the next run, to be rectified and refined with the mash. In that way, all of the types of whiskey we make have a little bit of every other batch we’ve made, creating a sort of “house flavor” for each of our products: we now have a continuous batch of bourbon feints, and soon we’ll start one for rye. When, you know, we start making rye.
Next up: barreling!
Batch two – contents:
Corn – 450 lbs.
Rye – 150 lbs.
Malted rye – 50 lbs.
Malted barley – 200 lbs.
And as promised, more fun* things to google!
- alpha amylase
- batch distillation (we do that)
- continuous distillation (we don’t do that)
*we guarantee it!**
**not a guarantee.