Crazy acid additions

[DrWill]

We are adjusting our Oud Bruin in the bottles. It has some nice sourness but we wanted to amp it up with an addition of straight lactic(88%). I wouldn't want straight lactic to be the only acid in the beer, but building on existing sourness should be ok.

We tested by adding acid to a 60ml sample. We found, bewilderingly, that the level of sourness we wanted was achieved with a staggering .75ml per 60ml sample. I couldn't believe this would scale up but indeed we put 4.5ml into a 355ml bottle, left it overnight and voilà it had the level we wanted.

I'm inclined to trust taste over numbers, but what do you think might account for these (I think) extremely high numbers?

 

[WI_Wino]

Do you know the mineral content of the water you used? If it was really high in bicarbonates it makes sense it takes a lot of acid to get the pH down.

 

[DrWill]

Water was filtered and pretty soft to begin with.

By the way, this is a finished beer, not a mash, in case that wasn't clear in the original post.

 

[505-Brewer]

Thats just over 1% by volume adjustment. Whats the pH of the Oud Bruin to start with?

 

[DrWill]

Thats just over 1% by volume adjustment. Whats the pH of the Oud Bruin to start with?

That's exactly what's throwing me off. We started with a pH of about 3.8 (higher than I want) but it's into the bottles now and so I can't measure it (these are heading to a competition.)

I'm wondering if the acid could somehow be bad? My organic chemistry sucks. (sorry, Dad, who was a toxicologist by profession)

 

[505-Brewer]

I would think lactic acid would be fairly stable. The dark malts in the beer might have some buffering effect. I don't see this as a large amount of acid added but then I don't know how much change in pH was observed. Best thing is you found a flavor profile you liked.
Good luck in the competition!

 

[DrWill]

I would think lactic acid would be fairly stable. The dark malts in the beer might have some buffering effect. I don't see this as a large amount of acid added but then I don't know how much change in pH was observed. Best thing is you found a flavor profile you liked.
Good luck in the competition!

I'll let you know how it goes! Thanks for the insights. Cheers!