I must be the only dork to do the math on his sacrificial run. It was my first time soldering and I’m super paranoid about having a leak so that’s why. I of course looked for leaks the whole time, even used a mirror to do so, but I can’t make this math add up so I’m wondering what I’m missing. Maybe my conceptual understanding of the numbers is poor.
Two inch pot still I recently built. Four foot Liebig. All on a 15 gallon milk can boiler. Only used the bottom element for this small run, it’s 1500 watts. I threw 2.6 gallons of cheap box wine in there (vinegar run was yesterday). They were 9% abv. So 2.6 times 0.09 is .234 gallons of pure alcohol. 2.6 minus that is 2.36. I had about 2.1 gallons of backset left. That’s not super accurate as it was measured with fermenter bucket markings.
I treated this like a spirit run to get used to my new rig. Without tasting, of course. Collected in 200 mL increments. Couldn’t believe it when it started slowing down and smelling like water. Proof hydrometer showed 17% when I quit. I got a total of 1500 mL (threw away 100 in fores) that came out to 37%.
So here’s what gets me. If you take that .234 gallons and divide by .37, I should have gotten 0.63 gallons, which is 2,393 mL. I got about 60% of that. But if anything I had less backset than expected, so it’s not as if I left a bunch in there. I mean I guess if the mixture ended up at 37% I could have gone longer, but I still thought the math above should work out either way (2,393 mL of a 37% mixture).
Again, I’m not super focused on yield and I know you get what you get. But I’ve done this same math on four stripping runs and I get 90% of predicted every time. Mainly I want to be safe and make sure I don’t have a leak I'm not seeing, but I also don’t want to waste my five gallons of hard earned low wines by doing something stupid with a new set up. Thanks in advance.

Did you calculate the alcohol left in the boiler? I'm not the best at maths but stopping at 17 leaves a fair bit behind" you can pick your nose and you can pick your friends; but you can't always wipe your friends off on your saddle" sage advice from Kinky Friedman

I thought that calculating how much would be present at a certain abv would account for that, but I’m all confused now. That’s how I’ve been doing it and it’s worked until now, so that’s what makes me think something went wrong on this one. But thanks for the thought, I’ll stare at it a bit more in a bit.

RU sure about that? Just because the box wine says it should be 9%ABV doesn’t necessarily mean it was.
Correct math. But this doesn’t include the fores you dumped, nor the alcohol you left in the boiler. Plus, it assumes the box wine actually had as much alcohol in it as the box said it did.
ssAttention new distillers: Cranky's spoon feed info
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Lots of opportunities for errors there. I wouldn't worry about it unless you did notice smells during the run.
I go over my stills with my nose, especially if I suspect I can smell product, as smell is usually a symptom of a leak, a restriction in the vapor path, or a lack of cooling water to the condenser.Last edited by NZChris on Sun Oct 16, 2022 11:35 pm, edited 1 time in total.

Nor 101 other variables......there is an old saying around here " you will get what you get"
If you've given the still a thorough going over visually, used a mirror and all of the other senses that nature provided you with , then you should be good to go. This hobby is as much a craft / art as a science.........sometimes pulling your hair out over a few numbers is just not worth the trouble.

If you got 90% of theoretical , thats pretty acceptable .
You done well .My recommended goto . /pic/wsjx2pmffu3 ... ory/theory
Some of it is outdated but most of the basics are correct .

RU sure about that? Just because the box wine says it should be 9%ABV doesn’t necessarily mean it was.
Correct math. But this doesn’t include the fores you dumped, nor the alcohol you left in the boiler. Plus, it assumes the box wine actually had as much alcohol in it as the box said it did.
ssGreat points. I guess I assumed the box could be trusted but maybe you’re right. Thanks!