by bluc » Sun Jul 14, 2019 7:49 pm
Pot still(air still as an example of a pot still) will smear, push late heads early tails into the hearts cut because it does not sepearte the fractions cleanly.
. Foreshots are the very first thing off the still and are usually disposed of in first run.(only in case of re running the same spirit).
if you have a big fermenter, more than you can run in one go, then you need to do fores cut on each batch that goes into the boiler(along with usuall heads hearts and tails cuts).
I recomend doing a fores cut even on a stripping run and disposing of that cut without smelling tasting. Just my opinion but concentrating the fores cut by distilling and doing cuts then saving up the fores is asking for trouble..possability of it being mistaken for hearts, being drank straight or mixed back into hearts giving that spirit a very high concentration of the nasty crap that is a part of distilling. If you must keep for colour them and label them clearly..
If doing a run and stopping mid way then starting again in a day or so, then ditching first jar. Is more a sub heads cut which wont be fores as such but may be a higher concentration of compounds found in the heads. Along with some compounds that form in the still, especially with copper stills that you dont want in the hearts cut.
Same thing happens in other stills, pot with thumper, plated column and reflux still just at varying degress. A reflux still as an example compresses the fractions a lot more and you get more defined cuts with less smearing but it still happens. Compounds in distillation are formed during distillation form during fermantation, mostly. There are some compounds that form during distillation like sters that are produced by different acids being boild along with ethanol, in some cases these are wanted especially in rum where long full reflux period can be beneficial to ester production.
I agree with the others that you should read kiwi distillers guide to cuts and re read it until you understand it. Hope this helps :handgestures-thumbupleft: