Infections

[Capt-Cudellez]

This question of infections comes up often on the forums, and was of grave concern to me when I started in the hobby. I've found if doing a sugar wash the reality for me is they really are quite rare if you get the yeast pitched quickly.
I am courageously lax with my sanitation, often not cleaning the fermemters between runs, or they usually just get a blast of hot water from the shower, and sometimes a quick scrub to rid them of the 'high tide' mark. I very rarely result to chemical warfare these days.

A while back I changed an ingredient in my yeast bomb, which unknown to me made the wash very acidic. I pitched the starter, closed the 2 x 50l ferments and went away for a few days.
When I came back, I checked on the fermenters expecting them to be close to dry, only to find them both inactive, and still reading 1.08-1.09 my Sg.
They were a bit cold, so I tuned up the heater, gave them a good stir and left them for another day - nada.

The next day I have the white spider web laco type infection starting, I have to go to work so it would have wait, 10 hours later the difference was impressive it was really starting to take hold. There was 22kg of sugar that I really didn't want to tip, and there was no bad odour that I could detect. So having now found the pH problem, I adjusted back to 5.5pH and pitched fresh yeast.

The wash started quickly, and by the time the initial foam cleared after a few days there didn't seem to be any sign of the infection. I know laco likes acid, so maybe the adjustment killed it off, or maybe the yeast did something or maybe just the ABV getting high enough. The wash did smell a little more cidery than usual when it was done, but not bad in any way, and reminded me a little of some turbo's I've used in the past, so might just be the amount of yeast in the fermeter.

The strip was fine, 'maybe' a little more odour to the low wines, or perhaps that's just me looking for something to be off. Ran it on the column yesterday and the results were good.

I doubt I would run anything that smelled "bad", but it looks like I've gotten away with a sugar wash sitting for the best part of a week, getting an infection, then getting it going.
So my advice to new distillers - if it doesn't smell off then run it, if you are not happy with the results then you can always chuck it later.

[chill]

And if you are still worried, take a look at what people are doing with infected rum dunder pits. And that is with a pot still! As we are not making beer or wine we seem to be able to get acceptable results even from an infected wash.

Chuck

[biopro]

In my formative years, my degree included microbiology. Yeasts are increadibly robust and most bacteria do not like low PH, hence the use of pickling to preserve foods. Most people don't realise that when farmers wrap hay in black plastic sheeting they are promoting an anaerobice environment to promote acetobacter to produce lactic acid to drop the PH and prevent any other microbes from growing and spoiling the nutrient quality of the hay.

So I expect the yeast outgrew everything else and the acid PH prevented mass outgrowth.

I am more cautious in my sterilising using whatever the call Chempro SPD nowadays. I use 1 tsp per galon and fill the bucket up and let it soak. However I do re-use the steriliser multiple times. They talk about oxidative reactions, which will decline very rapidly. As far as I can see, the steriliser is mainly an anionic detergent, which is why it shifts stains so well, in which case it will continue to lyse bacterial cells for ages.

Bacteria are actually very fragile. Hot water above 60C will kill most - but if there is a biofilm protecting small clumps they can come back very rapidly. Its spores that are problematice from a domestic setting as you cannot attain the pressure cooking temperatures to kill them. Tyndilisation is the only means available which means multiple sterilising - so the spore germinates and becomes a fragile bacteria and then gets bust by the detergent.

Even if I had a bad smelling wash, I would still put a batch through the still. I am putting some wine from 1970 through for a friend - it is all german and totally off. The product is interesting - there is a carry over in flavour but it has an interesting taste of its own. The worst wine I ever made was a bitter sweet elderflower and it fermented in a wonderful eau de vie style spirit.