10 replies to this topic

[Big Nake]

I'm close to the end of a bottle of lactic acid that I have probably been using for 6-10 months. The bottle always gets closed tight and is stored in my cool, dark, dry basement. I'm noticing that on my last 3-4 batches that I seem to need more acid to lower my mash pH simply compared to the same SRM beer that I have brewed in the past. My meter seems to be acting properly and it reads 4.00 and 7.00 solutions just fine. I suppose there could also be an increase in bicarbonate in my source water which is very possible. I just wonder if over time and when exposed to air (very temporarily), the acid in the bottle could "get weaker". Thoughts?

[positiveContact]

I would not have suspected that it would lose potency.  if anything I would think some water could evaporate and it would get more potent but if it's been sealed that seems unlikely.

[Murphy]

lactic acid has quite a long shelf life, when stored properly, and we are talking years. taking a pH of your lactic acid solution will tell all

[Big Nake]

lactic acid has quite a long shelf life, when stored properly, and we are talking years. taking a pH of your lactic acid solution will tell all

Ooh, interesting. Do we know what the pH of lactic acid should be? Something I found on teh Google machine shows a pH of 0.3 for 88% lactic acid.

[Bklmt2000]

Ooh, interesting. Do we know what the pH of lactic acid should be? Something I found on teh Google machine shows a pH of 0.3 for 88% lactic acid.

Ken, I did a similar search, and according to Archer Daniels Midland, the pH of an 88% lactic solution is 0.3.

 

And as said above, if kept properly sealed, lactic should keep its effectiveness for many years.

 

A quick test with a pH probe will confirm if the lactic acid you're using is still effective (my bet is, it's just fine).

[Murphy]

really the only way for a lactic acid solution to go back is if you allow the cap to be open for a decent amount of time and some of the water evaporates, but this would only produced a more concentrated solution, or if you cross contaminate the solution

[Big Nake]

What about the idea of shaking the solution before using it? Necessary? My last Ward Labs water analysis was in 2010 but I have seen posted water numbers by other brewers in my area and we all use the same water and the numbers are very similar. The most acid I would need in about 4.5 gallons of mash water used to be about 3ml for a very pale beer. On Monday I made a pale ale (SRM 7 or so) and needed almost 4ml just to get the pH to 5.39 which seems like a lot. I checked the meter directly after that and it read the 4.00 solution to 4.02 and then I calibrated the meter. I suppose it could be a springtime bump in bicarb or something.

[Murphy]

lactic acid is extremely water soluble so the likelihood of it precipitating is very very low therefore you should not need to shake your solution prior to use, although if you decide you want to shake it then go ahead as it won't do any harm

[positiveContact]

lactic acid is extremely water soluble so the likelihood of it precipitating is very very low therefore you should not need to shake your solution prior to use, although if you decide you want to shake it then go ahead as it won't do any harm

 

just make sure the lid is on tight!

[Big Nake]

Interesting. I'll take the pH of the small amount left in this bottle and see what it says. Thanks gang.

[SchwanzBrewer]

Don't cross the streams, Ken.