Yeast Washing with Citric Acid

[Redbeard5289]

Hello Fellow Brewers,

My apologies if this topic has been brought up before, I couldn't find any reference of this topic when I did a search.

Has anyone done ever done a yeast washing with citric acid before? If so, How did you do it?

The reason I ask is that I saw a brief mention of doing a yeast wash with citric acid (with a ph balance of 2.2) in one of the northern brewer catalogs a month or so ago. The little article blurp was talking about ph and the importance it plays in home brewing. Near the end of the ph article it mentioned that you could do a yeast wash with citric acid to kill off any other troublesome bugs that maybe in your yeast wash (with an exception to wild yeast, I believe).

I am interested in taking advantage of this for my next yeast wash, since I experience a mild bug infection on one of my yeast washes a year ago and it ruined a couple of batches of beer before I could discover the problem. I'd like to avoid that situation again

Any information would be greatly appreciated. I would love to hear your procedures and tips for doing a yeast wash with citric acid.

Thanks
Redbeard5289

 

[smokinghole]

I don't have my book with me right now but I think Chris White's book titled Yeast covers this a bit. It's a good book for all other topics too.

 

[Redbeard5289]

hey smokinghole,

Thank you for your referral about the new Yeast Book. The new Jamil and Charlie White Yeast Book is on my b-day list but I will probably be doing a yeast wash before my b-day comes around...

Would anyone else care to share. Any help would be greatly appreciated.
Thanks
Redbeard5289

 

[weirdboy]

OK so I cannot find the thread right now, but I had this question with someone else in a different thread that says they use phosphoric acid to wash yeast.

The idea is they add however much needed to bring the slurry to a pH of 4.2. I asked why couldn't you just use lemon or lime juice, which seems easier for the home brewer IMO. They said it would probably be fine, but they use phosphoric at work (presumable he works in a brewery) so that's what he uses at home.

So I think you're fine with citric acid, just mix up a solution and figure out how much you need to get the pH to 4.2. High school chemistry FTW!

 

[-TPM-]

I seem to remember reading that washing is pretty hard on the yeast. Just like the drying process, different strains of yeast will handle it better than others. Even on the more robust strains viability will be effected. It's not a silver bullet as it where for keeping clean yeast.

 

[Ichthy]

Here you go.

I use starsan.

 

[weirdboy]

Wow, 2.0-2.5 is pretty low.

 

[Ichthy]

Since starsan isn't effective at pH > 2 it makes sense. I've never had any problem using starsan. Though I do slightly overpitch if I acid wash a slurry; just in case viability was reduced.

 

[weirdboy]

Since starsan isn't effective at pH > 2 it makes sense. I've never had any problem using starsan. Though I do slightly overpitch if I acid wash a slurry; just in case viability was reduced.

I am pretty sure that number is 3.5, not 2.0.

 

[Ichthy]

My bad. It's apparantly a pH ~3.

 

[smokinghole]

hey smokinghole,

Thank you for your referral about the new Yeast Book. The new Jamil and Charlie White Yeast Book is on my b-day list but I will probably be doing a yeast wash before my b-day comes around...

Would anyone else care to share. Any help would be greatly appreciated.
Thanks
Redbeard5289

PM me your email I'll get you some info. I have multiple in depth brewing microbiology books.

 

[theredben]

Just wondering why you want to acid wash the yeast? Breweries use an acid wash to decrease bacterial populations since they re-use the yeast for upwards of 15 generations. For homebrewers it is cheaper to just use the yeast for half a dozen generations, and then buy a new pack.

Ph meters are not only expensive, they are very troublesome to use correctly.

 

[Woodbury419]

I personally don't know why when you conduct a search on Google and get hits on forums there is many that just flat out oppose to washing yeast with Acid. I conduct this every 5 starters my yeast goes through. My original yeast slant was Safbrew S-33, that yeast strain has survived over 10 5 gallon batches of Ales I've crafted and 18 starters or sustainment batches. I've made annotations with flocculation rates and at work I have an Inficon Hapsite SmartPLUS which is a GC/MS to monitor certain off flavorings in the headspace. I will agree that the yeast mutates, but the starters/sustainment i make are very consistent with the type of LDME/added nutrients/IBUs. I also made notes of the yeast under my microscope and compared to before/after starters and after my full batches of beer I craft. Many of the bad mutations occur in my yeast in high gravity brews obviously. Now, what I do for Acid yeast washing is I have my sustainment batch in a 1 liter flask. I decant the liquid and leave the slurry and I prepare in a 500ml beaker, 200ml solution of Star San and Citric Acid to a pH of 2.0 and another 250ml beaker 100ml of Star San and Citric Acid to a pH of 1.5. When I add the slurry the pH raises to 2.8 or higher depending on the amount of slurry I have. Then I add the solution from the other beaker until i achieve a pH of 2.2. I leave it sit out for an hour and during that time I prepare a 500ml batch of LDME w/ nutrients starter (OG 1.025) and allow it to cool. By the time it cools down I add the acid wash into the nutrient rich wort into a flitering flask and I attach my inline activated carbon/HEPA filter air line to the filtering flask and set on the magnetic stir plate for several hours. Then my yeast is happy again!

 

[Clementine]

Woodbury419 great post, love the info. I'm confused on the use of the Star San (I use idophor, so I have no hands on experience with the product). So is Star San just an acid based sanitizer or is there something more to it? Cutting it with Citric acid is that to raise or lower the ph?

Finally why doesn't the star san just kill the yeast as that is what it is meant to do? is it diluted more than normal? If so what approx ratios?

Clem

 

[broadbill]

I personally don't know why when you conduct a search on Google and get hits on forums there is many that just flat out oppose to washing yeast with Acid. I conduct this every 5 starters my yeast goes through. My original yeast slant was Safbrew S-33, that yeast strain has survived over 10 5 gallon batches of Ales I've crafted and 18 starters or sustainment batches. I've made annotations with flocculation rates and at work I have an Inficon Hapsite SmartPLUS which is a GC/MS to monitor certain off flavorings in the headspace. I will agree that the yeast mutates, but the starters/sustainment i make are very consistent with the type of LDME/added nutrients/IBUs. I also made notes of the yeast under my microscope and compared to before/after starters and after my full batches of beer I craft. Many of the bad mutations occur in my yeast in high gravity brews obviously. Now, what I do for Acid yeast washing is I have my sustainment batch in a 1 liter flask. I decant the liquid and leave the slurry and I prepare in a 500ml beaker, 200ml solution of Star San and Citric Acid to a pH of 2.0 and another 250ml beaker 100ml of Star San and Citric Acid to a pH of 1.5. When I add the slurry the pH raises to 2.8 or higher depending on the amount of slurry I have. Then I add the solution from the other beaker until i achieve a pH of 2.2. I leave it sit out for an hour and during that time I prepare a 500ml batch of LDME w/ nutrients starter (OG 1.025) and allow it to cool. By the time it cools down I add the acid wash into the nutrient rich wort into a flitering flask and I attach my inline activated carbon/HEPA filter air line to the filtering flask and set on the magnetic stir plate for several hours. Then my yeast is happy again!

Jeez, this just seems like alot of work to preserve a yeast strain that is readily available in any homebrew store for 3-4bucks....

I guess I'm also questions the need for this. I'm sure acid-washing is better than water-washing, but I'm also sure the acid wash isn't a 100% effective either...so at the end of the day it probably comes out as a wash (pun-intended).

Do the benefits of acid-wash really outweigh the extra effort?

 

[Woodbury419]

Woodbury419 great post, love the info. I'm confused on the use of the Star San (I use idophor, so I have no hands on experience with the product). So is Star San just an acid based sanitizer or is there something more to it? Cutting it with Citric acid is that to raise or lower the ph?

Finally why doesn't the star san just kill the yeast as that is what it is meant to do? is it diluted more than normal? If so what approx ratios?

Clem

Star San is indeed a phosphoric acid based sanitizer, the dodecylbenzenesulfonic acid is the portion that creates the "foam" and works harmoniously with the phosphoric acid by destroying bacteria's cell walls. I could go in depth on how it works...but I'm keeping it simple. I cut it with citric acid because I'm in the military and stationed in the UK. Star San is hard to come by and is fairly expensive after price exchanges. The ratio of Star San to water I'm using it at doesn't kill yeast, so if I happen to have a wild yeast contamination I'd have to scrap my yeast or attempt to isolate a the original strain from the contamination. The ratio's i honesly can't give exact specs on, i generally use Star San to get my pH under 3.0 and use Citric Acid to get spot on where i need to be.

Jeez, this just seems like alot of work to preserve a yeast strain that is readily available in any homebrew store for 3-4bucks....

I guess I'm also questions the need for this. I'm sure acid-washing is better than water-washing, but I'm also sure the acid wash isn't a 100% effective either...so at the end of the day it probably comes out as a wash (pun-intended).

Do the benefits of acid-wash really outweigh the extra effort?

Lol, yes you are correct and is much more work. I intend to open a brewery once Uncle Sam lets me go and I'm researching cost effective ways to help me along the way. Well, I never have attempted water washing. But in short washing yeast with Chlorine Dioxide, Acids, or water isn't fully 100% effective. The only way you can is isolating a single cell and propagating from there. Which without the proper equipment..is rather difficult. But I have seen some interesting things under the scope disappear after acid washing.

Please don't take this as something that has to be done, but it's another way to look at taking care of your yeasty friends. Cheers!

 

[Clementine]

I'm guessing your of the medical type, hence the procedures and knowledge of chemicals. I never knew that Star San did not kill yeast, I might stick with my idophor, does that kill yeast? I'll go do my homework on that. Thanks for the info.

Clem

 

[Woodbury419]

Lol, yeah I do environmental protection and in industrial hygiene in the military. But Star San can kill yeast, if the PH drops below 2. I'm not quite sure with idophor..I know iodine kills..but there's a level of lethality to the yeast. I would have to look at the msds and do some research.

 

[Woodbury419]

Not a problem clementine!

 

[runs4beer]

One reason pro brewers acid yeast is because the quanitys they need cost a bit more then a smack pack. As pointed out acid washing will not kill wild yeast which is just as common as bacteria infections, some bacteria will make it through. But it all about having fun and make good beer so do what you feel.