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General Category => Yeast and Fermentation => Topic started by: rbowers on August 07, 2015, 07:26:58 PM

Title: Lactobacillus and starsan
Post by: rbowers on August 07, 2015, 07:26:58 PM
I had a lacto starter all set for a Berliner Weiss brew day for next week.  I had some star San solution in the airlock and it appears (after placing in fridge to keep) that some star San was sucked back into the starter.  Knowing that starsan is an acid based sanitizer is there any reason to think adding a small portion to the starter by accident will annihilate the lacto which probably was already in an acidic solution from the lacto fermentation?  It was about a 1.75 L starter.  Concentration of the starsan solution unknown- just eyeballed it.
Title: Re: Lactobacillus and starsan
Post by: 69franx on August 07, 2015, 08:14:20 PM
When you say just eyeballed, do you mean you did not measure the stars an concentrate as you mixed it up? Probably still close though? Tough to guess without that info
Title: Re: Lactobacillus and starsan
Post by: reverseapachemaster on August 07, 2015, 11:17:49 PM
I'm sure you are fine. Unless you unloaded undiluted starsan into the airlock it's doubtful the volume of solution that was sucked back had any meaningful effect on the ph of the starter.
Title: Re: Lactobacillus and starsan
Post by: bboy9000 on August 08, 2015, 12:51:50 AM

I'm sure you are fine. Unless you unloaded undiluted starsan into the airlock it's doubtful the volume of solution that was sucked back had any meaningful effect on the ph of the starter.
+1 RDWHAHB
Title: Re: Lactobacillus and starsan
Post by: rbowers on August 08, 2015, 01:31:40 AM
regarding the eyeball- yes I just poured out a nickel or quarter sized amount in a medium sized tupperware container and filled with water.  I would guess its more concentrated than a five gallon bucket mixed up with recommended amount but likely no more than twice as concentrated.
Title: Re: Lactobacillus and starsan
Post by: johnnyb on August 08, 2015, 01:44:04 AM
regarding the eyeball- yes I just poured out a nickel or quarter sized amount in a medium sized tupperware container and filled with water.  I would guess its more concentrated than a five gallon bucket mixed up with recommended amount but likely no more than twice as concentrated.

A little less than a capful (at least the cap on my container which is similar to a 2-liter soda cap) is about the right amount for 1 gallon.

Title: Re: Lactobacillus and starsan
Post by: S. cerevisiae on August 09, 2015, 05:30:50 PM
Phosphoric acid is not the active ingredient in Star San.  The surfactant is what enters the cell and disrupts cellular activity.  The surfactant is drawn to cells that have a positive charge, which is why it ineffective at killing yeast and mold.
Title: Re: Lactobacillus and starsan
Post by: rbowers on August 11, 2015, 07:42:28 PM
So brew day went pretty well.  I have two batches of BW with lacto starters added and I am holding them at reasonably stable temps (100-110).  After 48hrs I decided to take a sample and the pH is only down to 4.6 and 4.5.  The podcast at the NHC I listened to seemed to suggest pH would be plummeting by day 2 or 3.  I had purchased a pH meter but unfortunately it didn't show up till yesterday so I was stuck with pH strips on the brew day which were not very helpful.  Original wort pH was around 5.2-5.4.  I added 1 tsp of 88% lactic acid and kinda chickened out on adding anymore.  Repeat pH per test strips was hard to interpret.  Would a single tsp of lactic acid added to 11gal of wort drop pH much?

It seemed like there was a fair amount of activity in the airlock (more than expected but not as aggressive as a primary yeast fermentation) so I assume something is going on.  Assuming this strain produces some CO2???

Specific Gravity today was roughly unchanged (not sure it is supposed to/expected to change with lacto)

It tastes not the least bit acidic which is frustrating.

So now I am at 48hrs of attempted wort souring, what to do?  Wait another 3-4 days?  I have a pack of Omega labs lacto so could always pitch that and see what happens.  Any advice?
Title: Re: Lactobacillus and starsan
Post by: johnnyb on August 11, 2015, 07:48:56 PM
Lots of people report long periods for some of the commercial lactos to work. I've heard of up to 7 days!

Pitch the Omega blend imo. You will be ready to rock n' roll within 24 hours probably closer to 18.