Sour Mash/Lactic Acid

So I'm wondering if I f-ed up yesterday.
I have moderately hard water and was brewing a rye Saison so I decided that some lactic acid would be just the ticket to lower my ph.
5 days before brew day, I put 2oz of pils malt in 120* water and let it get nice and stinky.

then on mash day, i checked my mash and added a little at a time until I was in range. I did a protein rest at 122 for 30 min, then slowly raised to 150 and let sit for 3 hours (I got 88% efficiency).

I then sparged, etc, etc.

I was reading today in New Brewing Lager Beer that lactic acid can ruin a beer DURING mashing.
Whats the deal, did I mess up bad with a 3 hour mash?

jason

What page? He may be referring to acidifying the mash without the intention of souring it. But you want it soured in a saison, so you should be fine.

The only thing I can think of, is that it will screw your conversion if you drop the pH significantly low. Voice of experience The method I am now working on is that I boost the temp very high and then just cover my tun and leave sit (a full sour mash). Thing is you gotta be careful, as it can run away once it hits the 130° and below range (they will keep working down into the 50's). I have noticed pH reduction happens very quickly once you get them in the zone.

pg 132-133.
He talks about the clostriduim bacteria which will turn the mash rancid if it sits below 140.
I let this mash sit for 3 hours at 150 so I'm hoping all is well

I'm pretty sure you're fine. Clostridium butyricum is a mesophilic anaerobe, meaning it prefers moderate temperatures (like 77-104dF). It doesn't quite read that way in Noonan's book because he sort of skips around in that paragraph, but it is not a thermophilic anaerobe. Plus you'd probably have noticed it stinking and rancid already anyway. Keep in mind that like it's brother, Clostridium botulinum, some strains of C. butyricum produce neurotoxins, so don't you go dyin' on us!:cross:

oh boy. I'll feed it to the dog first. Wait. make that the mother-in-law.
So, best practice for producing your own lactic acid is to pasteurize it at 140 BEFORE you add it to the mash?

instereo13 said:

oh boy. I'll feed it to the dog first. Wait. make that the mother-in-law.
So, best practice for producing your own lactic acid is to pasteurize it at 140 BEFORE you add it to the mash?

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Well, not really... you have to know here that there are 2 styles of bacteria that cause food-borne illness (well, really 3, but it's not worth getting into here). One is an infection caused by the bacteria itself, the other is intoxication caused by a toxin which is produced by the bacteria. So, if the bacteria have already produced the toxin, you could kill the bacteria and still have the toxin. Even boiling temperatures generally won't denature the toxin. Clostridium sp. are one of the genera that produce the toxin. So, pasteurizing would not get rid of it. I don't mean to scare you here. You're probably fine. As I said, you would notice it smelling rancid if you had a problem (butyric acid). I think C. butyricum infections in sour mash are fairly uncommon.

instereo13 said:

oh boy. I'll feed it to the dog first. Wait. make that the mother-in-law.
So, best practice for producing your own lactic acid is to pasteurize it at 140 BEFORE you add it to the mash?

Click to expand...

I'm telling you DON'T reduce your pH in the mash too far, you will regret it.

Anaerobic bacteria do not thrive in aerobic environments as well (and can die in the presence of Oxygen) so that is on our side. As for poisoning yourself, most of the time it is the living microorganisms that get into your system and then continue producing toxins that is the most dangerous state of affairs.

I was hunting for something that I knew was most likely the case. There was a publication on this.

"The aim of this project was to establish the minimal inhibitory concentration (MIC) of lactic acid for growth of Clostridium tyrobutyricum. A pH-auxostat was used to maintain a constant pH and to allow continuous growth at the highest possible rates at fixed, but adjustable concentrations of lactate. By raising the concentration of lactic acid and keeping the pH constant, the growth rate was shown to decrease linearly with increasing lactic acid concentration. The pKa of lactic acid, measured in the actual growth medium at 37°C, was 3.40 (±0.03). Based on this value, the MICundiss values for each pH were estimated. The MIC of total lactic acid (MICtot) ranged from 150 mmol l−1 to 1510 mmol l−1 at pH 4.6–6.25, respectively. The corresponding MIC values of undissociated lactic acid (MICundiss) ranged from 8.9 to 2.1 mmol l−1 at the same pH values. These results emphasize the importance of a rapid pH decrease and an equally rapid initial lactic acid fermentation of the ensilage, in order to sufficiently suppress clostridial growth."

I have a feeling after digging into this some more, that the dominant Clostridium (if any at all) that would set up shop would be Tyrobutyricum (because it is mainly interested in Glucose) especially if your pH doesn't drop sufficiently in enough time. That all being said, you have to rely on your own judgment in these matters.

just to clarify: no human pathogen can live in beer....right?

instereo13 said:

just to clarify: no human pathogen can live in beer....right?

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The low pH (and even lower in the case of soured mash beer) and alcohol pretty much make this next to impossible. I have never heard of this ever occurring, and the topic comes up every now and then. This is one of the miracles of fermentation we can be thankful of!

Update, I did a recipe with the full mash souring...be very careful if you do this. Not that it will be dangerous, but you can easily overshoot the sourness level if you let it go too long and I do detect the 'rancid' property in it (grumble grumble). I am going to give the full mash souring one more go round, but this time I am going to be much more proactive in monitoring the state of it.

aside from the rancid issue, is tannin extraction a problem? I know if you ferment beer with the grains left in (like in whiskey) a lot of tannins get extracted, is it not an issue with such a small volume of grain or are the acid producing bacteria not prone to tannin extraction?

No because the temperature stays low enough, at least this is what I am hypothesizing. I have not noticed any excessive Tannins in the brews that I have soured.

cool, I love playing around with different microorganisms. I'll have to try this method, although I think I'll have to add some carbonate to my water before otherwise the Ph might get too low.

k1v1116 said:

cool, I love playing around with different microorganisms. I'll have to try this method, although I think I'll have to add some carbonate to my water before otherwise the Ph might get too low.

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Well the thing is, I have found as long as you convert first, sour second you are fine. Adding sour mash to the tun before conversion is a bad idea because that can and will interfere with conversion if you add enough. So I am not sure you need the carbonate. I am guessing, if you do the full sour mash, start watching it like a hawk after 12 hrs. And if you sample it from the tun to test the sourness, stir it up first as there seems to be stratification of the sourness for some reason.

hey, i did a rye saison last weekend too! i'm fermenting it with wlp565 - split between two caboys, one in the garage at about 88 - 90 deg. and the other in the utility room at about 78 - 82 deg. for comparison.
my grain bill for 11 gallons:
20# belgian pilsner
2# flaked maize
1.5 malted rye
1.5 malted wheat
1 cara-pils
i did a step infusion mash with rests at 113, 132, 145, and 158 before mashing out at 168. despite using ph5.2 (and adding more) i couldn't get the ph below 5.5. despite that, i still had 83% efficiency (1.074), which i was o.k. with.
i thought about doing a sour mash before for a lambic, but after doing one straight with wyeast's lambic blend, i didn't see the need for it. it gets plenty sour. is there another advantage of doing a sour mash (other than the ph effect and maximizing efficiency)?