Really low finished beer pH

[motobrewer]

I made Orfy's Mild - used 0.4 g/gal of CaCl2, CaSO4, and NAHCO3 in the mash and sparge (from RO water). Mash pH was 5.25. Post-boil was 5.08.

Post ferment, pH is 3.98. I thought this was really low. Taste is a little on the tart side.

 

[ajdelange]

First question is as to whether those measurements were made with a properly calibrated and stability checked meter or strips. If in the former case we can only note that some ale yeasts will indeed take beer pH that low but it's not usual and I'd be looking for the possibility of infection (Lactobacillus). If, OTOH, the measurements were made with strips they are all probably 0.3 higher and the beer pH is probably around 4.28. Still pretty low.

 

[motobrewer]

measurements were made with this:

http://smartaquameter.com/sam1-2000.html

and cal'd with sensorex buffers.

 

[ajdelange]

Assuming that this meter passes a stability check then I think you need to seriously look at infection.

 

[motobrewer]

Assuming that this meter passes a stability check then I think you need to seriously look at infection.

I haven't done a stability check in about 9 months with this meter but if I recall it was .01 drift over 2 hours.

How do I check for lacto?

 

[ajdelange]

Easiest way is a microscope. OW about all you can do is look for turbidity and lactic acid flavor.

 

[motobrewer]

Easiest way is a microscope. OW about all you can do is look for turbidity and lactic acid flavor.

If there was a lacto issue would you expect the pH to keep dropping?

 

[ajdelange]

To a point. When there is nothing more for them to ferment they will stop fermenting and cease acid production. If you do see pH continuing to drop I'd call that pretty solid evidence of infection as the yeast finished their pH adjustment long ago.

 

[zwiller]

I am making large assumptions that:
1: you used an english yeast
2. english yeasts reduce pH more/produce more acidity than neutral american yeast (based on posted data)

I think mash pH was on the low side for a mild and would aim 5.6ish for a ruby colored one with english yeast. Good news is a tad of pickling lime might fix it. Try and dose a pint, then scale up. I vote against infection unless extended aging occurred, which I doubt in a mild.

 

[motobrewer]

It was an english yeast; US-04 to be specific.

Also it was a darker version at 20 SRM. 4% simpsons chocolate malt and 18% simpsons medium crystal (67 SRM)

 

[zwiller]

Recipe sounds darn good.

If you dig a little you will see some guys like me trying to collect data points relating to final pH. There is a consensus at this point that American/Neutral strains produce less acid while English and other strains produce more. Very unscientific at this point but I think more data will continue.

I have brewed long enough that I have come to prefer darker/english beers with a higher mash pH. Smooth things a bit and accents malt I think. It just so happens since english yeasts produce more acid you can get away the technique since the final pH will be on target... American beers are the opposite, use a lower mash pH since the yeast needs some help to drop it.

I would still try the pickling lime or baking soda in a pint for giggles.

 

[motobrewer]

I will, once I get it into a glass. It's still in the fermentor.