From what I understand, when one is distilling ethanol one does not use the first portion of the run or the tail end since those contain crap that you don’t want in the product. So is it possible to take the discarded portions and re-distill them for usable ethanol? Or is it too dangerous/unprofitable? What can the discarded portions be used for? Industrial uses?
If you monitor the temp you will see that anything that come off before 173 degrees I believe is volatile other than ethanol and should be discarded. No one runs it back through for a good reason.
You discard the first little bit that comes off at ~165°F IIRC, that’s methanol heads and that’s poisonous. After the temp gets up to ~173°F, then it’s ethanol, it’ll rise up pretty quick after the methanol is cooked off. As the distillation progresses, the temp will maintain a fairly constant temp, the hearts, but will rise as the proof falls off.
If you distill all the way up to 212°F, that’s water. So cut off at 70~80 proof or so, or at least no more than 200°F. You get more “funk” towards the tails, so don’t get too carried away with trying to get the last little bit of ethanol out of the still. You can just ad what’s left to the next batch, like sourdough starter, or toss it out and strart a fresh batch.
Or so I’ve been told.
There are really 4 phases to a distilling run- the “foreshots”, which is composed of the most volatile compounds like acetone, the “heads”, which are less volatile, but may contain ethanol, the “hearts”, which is the main ethanol distillation, and the “tails” which are less volatile, and contain a good proportion of water.
The foreshots are typically discarded, but the heads and tails are sometimes thrown back into the next run for the purposes of getting that last bit of ethanol, AND because they also contain a good deal of the flavor compounds. Other distilleries will save them up and redistill them by themselves and make a “queen’s share”, which will be more complex and flavorful than a typical distilling run.
I did a tour of the Bombay Sapphire distillery just last week. The heads and tails are collected in a separate tank and sold to companies who need industrial alcohol. The guide listed several products it’s used in, but the only one I remember is perfume.
Interesting. Thanks!
Gin processing is a little different because there are botanicals in the mix for the second distillation, so the heads and tails have a little more unwanted compounds and aren’t good for blending back into the next batch. As you note, they are used in a variety of applications, but not as-is; first they are redistilled to a neutral spirit (95% alcohol).
Yeah, you wouldn’t probably blend them back into a vodka distillation run either, as it’s supposed to be very neutral anyway.
Another thing to consider is the type of still; pot stills are more prone to having less distinct boundaries than the various sorts of column stills, in that it’s totally based on time and temp as to what’s coming off the still when, and there’ll be some degree of water and ethanol coming out in the heads as well as the tails.
With column stills, the whole point is for everything to essentially fractionate out in the column. Then you can either tap the column at the ethanol height, leaving the rest behind (there would be very little heads or tails in this situation), or you can run it out the top, where it will have been very clearly separated by the column as it comes out of the condenser. In that case, the important thing would be to make your cuts at the exact time that you quit getting toxic or unpleasant compounds out, and at the point when you started getting an appreciable amount of water.
So how did the old moonshiners know when to start saving the condensate? Obviously it wasn’t a perfect system, hence the warnings about going blind. Was a good thermometer a part of every moonshiners kit? Or did they sniff the vapors, taste the drops, etc?
Dennis
First, to correct a common misconception, no one went blind because moonshiners left too much of the heads in their booze. The amount of methanol created in fermentation is minuscule and not enough to cause problems with toxicity. Methanol and other crap at dangerous levels in moonshine was the result of people mixing in methanol on purpose to save money, or running their distillations through old carburetors that hadn’t been flushed.
As for how moonshiners knew when to cut the heads and hearts, it is by smell and taste. As you get experience in distilling, you can get pretty good at identifying the non-ethanol compounds in the heads and tails.
As bump described above, temperature is a pretty good measure of what’s in the distillate in a column still with good fractionation, but it’s not much more than a general guide for pot stills used to make moonshine.
I can’t figure out just how a carburetor would be useful in a still- did you mean radiator? There’s a difference. Also, I think the danger of old radiators was from the lead solder in them.
I have read that yeast don’t make methanol from sugars, only from pectin. Is this true? If I were to make a few gallons of brew from only yeast, water, and sucrose, would the result have any methanol in it?
Also, there’s a visual component, called “beads” or some term like that. When different fractions come over, and mix drop-wise, there’s a refractive index change – they mix, “swirly” before they mix completely. The moonshiner is supposed to be making something they intend to consume themselves, so they’ll deliberately discard some good with the bad to make a “heart cut” that they’d be proud to share with the good ole boys.
Heh, right. Glad I only had to type that, and not say it.
:smack: Right, I don’t know where I pulled carburetor out of. Brain fart. Lead and other metals are always an issue with **radiators **, but other nastiness can also be present from coolant or oils. If it’s a junked radiator, who knows what might have been leaking into it.
You can get very small amounts of methanol from any fermentation, but you are right that pectins usually create more. Even then, it’s not at levels that will harm you. You’d have to drink enough that the ethanol will kill you first.
I wasn’t aware of that but am glad you posted it. I have cooked down batches of wine I didn’t like and used it to fortify other wines. Grapes have considerable amount of pectin and is not considered any kind of a hazard. It would be about 5 times more concentrated if cooked down into alcohol.
Yeah, if you think about it a little bit, you’ll realize that you don’t get any MORE methanol or other undesirable compounds overall out of a given distilled batch of something than you would in the original fermented batch. So if you have a 5 gallon batch of wine, that has the same amount of methanol, etc… as the final distilled product will. It follows that a glass of wine is going to have the same amount of bad stuff as the same quantity of distilled product having the same amount of ethanol, IF the distillers didn’t toss their
foreshots, heads and tails.
In other words, to sort of follow up on HoneyBadgerDC’s comment, it’s 5x more concentrated, but you drink 1/5 the amount. So even without throwing out the heads/tails, you aren’t in any danger.