Chlorine Dioxide

[trtedrow]

We're interested in using Chlorine Dioxide to wash our yeast for longer storage. What ppm concentration should we be using? Also, how many mL solution should we be using per Liter of yeast slurry? Thanks a bunch,

Travis

[JoeV]

Oxine wash

I have heard between 20 and 40 ppm. The ammount to use would depend on how much yeast you are washing and how concentrated your Oxine stock is. Your chemical vendor should be able to help you out with use concentrations. IDD website has a nice blurb on oxine as do a few other sites just google it. I seem to get some colficting information on when to wash, just after harvesting or just before pitching. I to am intersted in oxine in general and would like to hear others experiences with it as a sanitizer, washdown water additive, keg sanitizer and so on.

[Rob Creighton]

I am using a 30 ppm solution for yeast washing. We receive it at 800 ppm concentration and make sure that all our spray bottles and dispensers are opaque to prevent light degradation.

I like it because it is our sanitizer as well as yeast washing solution. You have it in all your yeast handling containers as well as sprayed onto all fittings and need not rinse or worry about cross contamination. Plus it doesn't have the same lethal effect on yeast as acid. Very user friendly for a small facility like ours. The test strips have made it easy as well.

[trtedrow]

30 ppm for chlorine dioxide

Rob, this sounds great thanks for the reply. At 30 ppm, how many mL of ClO2/kg of yeast slurry are you using? I wasn't sure of the ratios.

Travis

[Rob Creighton]

30ml of 800ppm ClO2/litre of yeast is giving me a 30ppm solution.

[william.heinric]

ClO2 as a sanitizer

When used as a general tank sanitizer, does it kill off the residual yeast in the tank? If it doesn't kill yeast in the wash/storage phase, I'd be worried about strain cross-contamination in the fermenters.

Bill

[gitchegumee]

We used chlorine dioxide to wash yeast at a brewery a long time ago, but only immediately before pitching. There's a guideline somewhere that correlates pH vs. time before pitch for effective acid washing; there should be something similar for chlorine dioxide as well. Talk to the supplier/manufacturer. Best of luck.

[dick murton]

We used chlorine dioxide to wash yeast at a brewery a long time ago, but only immediately before pitching. There's a guideline somewhere that correlates pH vs. time before pitch for effective acid washing; there should be something similar for chlorine dioxide as well. Talk to the supplier/manufacturer. Best of luck.

I've never heard of ClO2 being used for acid washing. I would expect if to kill off yeast and bacteria almost equally as well. I'm intrigued - have you any more details ?

Using phosphoric acid - keep below 3, 4 absolute max, pH 2.2, maximum time 4 hours, gently mix all the time. This is generally considered good (effective) practice

[gitchegumee]

Hello Dick! That was 15 years ago. But we did use it to sanitize, too. And we had multiple strains of yeast, so obviously we would have used a sanitizer that was effective on yeast. I don't remember how the stuff works, but at small doses it would wash yeast. I do remember that measuring the pH of the yeast would fry our pH meter all the time for some reason. And the product was called Oxine. Used it as a final rinse in a twist rinser and applied it as a mist on crowns too. Sorry I can't come up with more--I haven't used it since.

[Woolsocks]

I've attached a document on this from Birko, as well as a document from the Brewing Science Institute discussing their method for doing it under "yeast harvesting and storage". I use this method and it works well. Be sure your Clo2 product is the same concentration they use in the "instructions". Oxine is weaker than the product from Birko, for example, so you have to use more.

[dick murton]

Thanks for the info guys. A bit more to tuck away. I won't have the opportunity to test this out with the current employers - plant hygiene and frequent reculturing make it unnecessary. But one day who knows what I will be doing

Cheers

[Woolsocks]

Basically the deal is it takes a lot higher concentration of ClO2 to kill yeast than it does bacteria. So, you mix it up real weak and add it to the yeast. Your yeast is largely unaffected and the bacteria gets killed. Wild or mutated yeast is, of course, minimally affected.

[Geoff Logan]

3mL per gallon of slurry is my guideline

[JoeV]

concentration vs. kill

So far this is what I have come to understand with oxine.
Yeast washing at 20-30ppm kills bacteria leaves yeast un-harmed, we get viability of over 95% with methylene blue counting. We even store the yeast for up to a week, on ice, fed with sterile (autoclaved) hopped wort.

At 100ppm it kills yeast, bacteria, and mold.

It gets kind of expensive at 100ppm so we use PAA in our fermentors and 50ppm oxine on anything that touches finished beer. Anything that touches yeast for re-pitching gets 100ppm oxine.

With the concentration of oxine we are supplied 2ml per gallon of thick slurry is what we are using. We activate it first then add to the slury, at the same time we "feed" the yeast if we are not going to pitch it within 24hrs.

[benself]

yeast washing

I'm not sure about using dioxy-chlor in tank sanitation, but I do know that ClO2 doesn't work unless it has an acid source to convert it to sodium hypochlorite (bleach) in solution. Use 10-15 drops of 15% lactic acid with your solution, and let it sit for 10 minutes before adding it to the yeast.