Shelf life of Lactic Acid

[BreezyBrew]

I came across something interesting today;

I needed some more lactic acid, so while I was at the store I picked some up. The older bottle is about two years old, and both are 88% concentration. The older bottle is Baker and Crosby and the new one is BSG. After smelling them both, there's definitely a difference there. The older bottle smells more sour and acidic, where the new one smells almost like maple syrup. Should this matter in their performance? I am thinking that what they use to cut the solution is different, which is why they smell different. Maybe someone can shed some light on this?

 

[stpug]

I experienced the same when switching brands (B&C became BSG). However, I do not find that the scent/flavor of the BSG stuff comes through in any way. I would simply say "carry on".

 

[mabrungard]

I don't believe that lactic acid will go bad. It can be adulterated, but not go bad.

 

[mchrispen]

I don't believe that lactic acid will go bad. It can be adulterated, but not go bad.

Lactic acid happens when bad lactobacilli have adultery... just saying.

Sorry - just had to.

 

[TNGabe]

Lactic acid shouldn't smell like maple syrup.

 

[stpug]

I don't get maple syrup but more of a sweet/sour aroma. Regardless, it doesn't carry through to the finished beer.

 

[ajdelange]

This is an uniformed speculation but when one sees a -ol group hanging off the side as in lactic acid: CH3HCOHCOOH
one is tempted to think it will get oxidized to a keto:
CH3COCOOH
in the presence of oxygen from air exposure i.e. convert to pyruvic acid. That might explain the sharper smell.

 

[MNDan]

Would pyruvic acid contribute to the characteristics I am tasting in the recipe below? I am still guessing it is due to some grassy/bad amarillos, but the tartness is an interesting part of the flavor that I have trouble blaming on the hops. The 4 ml of lactic acid I added is from a bottle that is probably a year to two years old and has sat in my garage the entire time.

https://www.homebrewtalk.com/f14/help-me-my-pa-really-sour-weird-hop-flavor-w-amarillo-citra-480750/

 

[malhal]

delete