Residue on PET yeast bottle and fermenter

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Residue on PET yeast bottle and fermenter

Post by Jaydee » Sat Sep 12, 2020 3:14 pm

Hi all,

I’d cleaned up after my last brew day using PBW and then Starsan to sterilise. I’ve now found that I obviously neglected to rinse thoroughly and I’m left with a hazy residue inside my PET fermenter and my yeast harvesting bottle.

I’ve tried PBW again and a 12 hour soak in Starsan but still have the problem.

I am in a hard water area, alkalinity of 220 ‘ish. Could this just be calcium deposits and nothing to worry about?

I would like sparkling equipment - any thoughts on how to remove the deposits?



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Re: Residue on PET yeast bottle and fermenter

Post by Carnot » Wed Sep 23, 2020 11:33 pm

I think that your problem lies with the PBW which is a mix of sodium percarbonate and sodium metasilicate. This will raise the pH and combined with your hard water it has possibly caused carbon dioxide to react with calcium ions and precipitate. The long soak is the problew.

I have never been a fan of Starsan and cannot understand why some many consider it a sanitiser when in fact the best it can really do is act as a biostat. All Starsan contains is a mix of phosphric acid and DDBSA (dodeclybenzene sulphonic acid). The DDBSA acts as a surfactant and the phosphoric acid acts as a rather poor biostat.

Neither treatment will shift the hazy deposit. If you have some CRS or even better hydrochloric acid I would add this as a dilute solution to your vessels and it will robably dissolve the deposits. It might need a soak. You would need to get the pH down to about 3. An alternative would be a kettle descaler which is usually sulphamic acid.

I use two food grade cleaners on my equipment - Amphoclen and Trio 100 . Both work well and are available on eBay. I aslo sterilise with sodium percarbonate all the small pices of equipment such as blow off traps , tubing and valves. So far I have never had an issue with sterilasation. I make a lot of mead which is made naturally without heat or any sulphites and good cleanliness is imperative.

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