ph, buffers, yeast, and hefeweizen

[ebbelwoi]

I think I've got relatively soft water:
Ca: 8
Mg: 2
Na: 8
Cl: 12
SO4: 29
HCO3: 2
...or thereabouts.

One of my favorite beers is hefeweizen. Unfortunately, my hefeweizens end up a bit on the tart side (if I use WLP351/WY3638) or pretty darn tart (WLP300/WY3068).

I've really looked into this. I've read the braumagazin article on Weissbier in both English and German, and I've read several threads on hobbybrauer.de about tart weizens, and read every post I could find in English. I've looked at many possibilities (natural tartness of wheat malt, possible infections, sensory effect of pH lowering by yeast vs. adding lactic acid), but today I'd like to ask about one in particular.

I understand that yeast like to lower the pH of their environment, perhaps WLP300 moreso than other strains. What I'm wondering is: does this lowering of pH have a stronger effect (on the palate, not necessarily the pH meter) if the brewing water has lower buffering capacity? If I were to increase my water's buffering capacity, would it be more resistant to a pH drop? Or at least sensorily?

Even the Germans at hobbybrauer.de are scratching their heads on this one. Any ideas?

 

[mabrungard]

That water has very low alkalinity. With the typically very pale grist in a Weizen, I would still expect that a touch of acid would be needed to bring the mashing pH into a desirable range. Assuming you’re not overdosing with acid, I don’t know why the beer pH would be overly low. Many weizens I taste that haven’t been properly brewed suffer from a darker color and dull flavor due to a high beer pH.

 

[ebbelwoi]

From the start, I've been mashing with a high pH (5.8-ish) to encourage ferulic acid production (as per the braumagazin article). For the last few batches, I've started adding lactic acid post-mash/pre-boil, and again with 5-10 minutes remaining in the boil. It's resulted in a less tart beer, but the tartness is still there. Color is exactly where I want it, and the flavor is really close as well. It's the tartness that's got me wondering. Maybe for the next batch, I'll skip the bottle conditioning and try kegging.

I don't have a pH meter. I've come close to buying one, but every time I start reading reviews for one product or another, I get scared off by someone saying it's junk.

Martin, do you figure I'm barking up the wrong tree with buffering here?

 

[VikeMan]

I understand that yeast like to lower the pH of their environment, perhaps WLP300 moreso than other strains. What I'm wondering is: does this lowering of pH have a stronger effect (on the palate, not necessarily the pH meter) if the brewing water has lower buffering capacity? If I were to increase my water's buffering capacity, would it be more resistant to a pH drop? Or at least sensorily?

If your wort's buffering capacity were higher, it would be more resistant to pH change. And starting with water with a higher buffering capacity should yield a wort with a higher buffering capacity.

But I agree with @mabrungard... you'll still need some additional acid (by a direct acid addition or by adding calcium) in the mash to get its pH in line. As mentioned, it's a pale grist. And it also has a high percent of wheat malt, which contributes less acidity to the mash than other base malts.

 

[ebbelwoi]

I add enough calcium chloride to get me to about 40ppm Ca and 70ppm Cl, fwiw.

 

[Vale71]

People often mistake the PH value with "tastes acidic". Our taste buds are not sensitive to PH value but to the actual acids in what we are drinking/eating. Different acids cause different reactions in our sense of taste regardless of actual PH value. For example, RO water if left in the open will stabilize at a PH of about 5.6 which is already well into the acidic range but if you drink it it will still taste like pure RO water, i.e. like nothing at all. That's because CO2 doesn't really have a taste, unlike organic acids such as lactic and citric that have a distinctive taste.
So, to answer your question different beer styles have different levels of "tartness" because different yeasts and/or worts of different composition will have a different mix of organic acids causing different reactions in our taste buds.

 

[Vale71]

Here's some in-depth reading if you're interested in the physiological aspects of sour taste perception and why different acids elicit different responses.

https://www.pnas.org/content/113/2/246

 

[mabrungard]

From the start, I've been mashing with a high pH (5.8-ish) to encourage ferulic acid production (as per the braumagazin article). For the last few batches, I've started adding lactic acid post-mash/pre-boil, and again with 5-10 minutes remaining in the boil. It's resulted in a less tart beer, but the tartness is still there. Color is exactly where I want it, and the flavor is really close as well. It's the tartness that's got me wondering. Maybe for the next batch, I'll skip the bottle conditioning and try kegging.

I don't have a pH meter. I've come close to buying one, but every time I start reading reviews for one product or another, I get scared off by someone saying it's junk.

Martin, do you figure I'm barking up the wrong tree with buffering here?

Adding acid without guidance or a pH meter, could be resulting in an overdose and a lower than desirable wort and beer pH. If you're conducting post-boil lactic or saurergut additions based on someone's recommendations that were built on their water, that could easily explain a more tart result with your low alkalinity water. It just doesn't need much acid to bring the pH down.

 

[ebbelwoi]

I've been using estimated pH values based on my water report and brewing software (Brewfather).

I got more perceived tartness when I didn't add lactic acid to the mash or boil. The tartness has decreased since I started making smaller additions. The guidance I received in this forum was that lactic acid (and presumably associated compounds) generated organically, by yeast, have a greater perceived tartness than inorganic lactic acid. The advice was to give the yeast a headstart in lowering the pH at the start of fermentation.

Martin, if you tell me I need to get a pH meter to make headway on this, I'll bite the bullet and get one.

 

[Vale71]

I've been using estimated pH values based on my water report and brewing software (Brewfather).

I got more perceived tartness when I didn't add lactic acid to the mash or boil. The tartness has decreased since I started making smaller additions. The guidance I received in this forum was that lactic acid (and presumably associated compounds) generated organically, by yeast, have a greater perceived tartness than inorganic lactic acid. The advice was to give the yeast a headstart in lowering the pH at the start of fermentation.

Martin, if you tell me I need to get a pH meter to make headway on this, I'll bite the bullet and get one.

I guess that advice came fromt he "Sauergut" camp, right? I'd like to hear their explanation of how the same substance with the exact same chemical composition could give different results depending on whether it was refined from a culture or produced on-site by yeast. FYI what they called "inorganic" lactic acid is refined from a bacillus culture so I don't see why it would be considered "inorganic" only because it's refined and concentrated.
Again, IMHO you shouldn't fixate on PH value since it is of little significance as far as perceived tartness goes.

 

[mabrungard]

Martin, if you tell me I need to get a pH meter to make headway on this, I'll bite the bullet and get one.

No. If you're using software that you like and it seems to be producing good results, you don't HAVE to use a pH meter. Many good programs can get you close enough to enable you to produce good beer. The time when you might want to have a meter is when you can't decipher your results.