Smelly Strip

[Almanac]

I was stripping a sugar wash of some 80lt on Monday and split it into two parts to fit in my 50lt Keg. First batch was routine but while it was running I decided to check the pH of the balance and found it was just 3.4 and decided to adjust the pH to a more neutral level.

I first added some Precipitated Chalk but the effect was minimal and 50g only brought the pH to 4.2. In desperation I searched my Chemical stock and found a 100ml bottle of Acid Reducer (basically a pre-mixed solution of Potassium Carbonate.) Again the effect was quite small and brought the pH to 5.4. At this stage the wash was quite cloudy with all that chalk in it so I decided to get to the bottom of the problem and put off finishing the second part of the strip until Wednesday.

I had just taken delivery of 1kg of crystalline Potassium Carbonate but hadn't even opened it. I decided to use some to get the pH where I wanted it and the instructions said 1g per 10lt would make an adjustment of 1 ppt. With 40lt now 1.6 off ideal pH I decided to add just 30g (erring on the cautions side) the pH moved up to 6.7 and I decided to leave it at that.

This morning I was transferring the wash to the boiler and noticed a slight film on top of the wash but as it was going in the boiler i decided it was not a problem. I started the boiler on the timer and came back to the garage to start the coolant when the boiler temp had reached 75oC. I estimated another 20 mins before first product and went back into the house. When I returned product had just started and the alchometer had just started to lift in the parrot - but the smell...smelly feet and it wasn't me

I've read of this effect but can't for the life of me remember where or what the cause is but we must surely have the expertise here to remind me what causes this phenomenon.

AM

[Capt-Cudellez]

AM, not sure what has gone wrong, and I'm not sure from reading the post if you were adding all those chemicals to the same wash or different batches.
I've always been told that adjusting washes is a bad idea. The adjustment should be done prior to the spirit run by which time you have already left all sorts of undesirables in the boiler from the strip, even then not being a chemist I would only use a single chemical to adjust the pH.

I have only ever adjusted a wash when its stalled mid way (or not started at all) to make it a happier place for fresh yeast to get going. My wash is often in the low 3's when I strip it, and I don't have any issues with off tastes or smells.

I only ever treat low wines to avoid ester creation during the long equalisation on the spirit run for neutral (I only actually do this with all heads runs. Although now I'm keging my low wines, I might try this again to see if I think its worth it).
I actively encourage then esters when doing my rum.

I can't point you in the direction of a post that explains why I do this, its more the accumulation of lots of posts, and some reading between the line. So I may be completely wrong on all of the above - but I haven't had a strip that smelled of feet. I've had a few rum strips that smelled of sulphur but that is down to the molasses and forgetting to add the copper pieces to the strip head I think.