pH from Mash to Beer and Stability

[tezcatlipoca]

Hi guys,

I just recently bought a pH meter. So, now I have more information than what I know what to do with. I have been reading about pH throughout the brewing process, but the bulk of the info I've been able to find is just about mash pH. From what I can tell, the ideal mash pH for extraction of fermentables is 5.5 with a range from 5.2 to 5.7. Other people say that the beer tastes better if the mash pH is driven down to 5.2.

Ok, so I brewed a beer a couple weeks ago and aimed for 5.3. Hit 5.3 perfectly. Great brew day. I left it ferment out and measured the pH of the sample I pulled for a gravity reading. Gravity 1.012. Starting was 1.061. pH was 4.52.

I've read that 4.2 to 4.5 pH is the range for microbially stable beer. The lower end of that range seems to be better. I understand that the yeast will drive the pH of the wort down as it becomes beer and that if you leave the beer on the yeast cake too long, your beer's pH will start to slowly increase. So, in order to brew microbially stable beer, do I need to take it off the yeast faster than two weeks? Do I need to start with a more acidic mash? It kind of seems to me that if I wanted microbially stable beer, I would have to brew just outside the range for ideal fermentable extraction, i.e. lower than 5.2.

All in all, this beer tastes good. I'm more interested in this for future endeavors. I don't think I have a problem persay, but I'd like more understanding. Cheers!

 

[mabrungard]

While the brewer can manipulate the wort pH, it is the yeast that set the beer pH. Moving the wort pH up or down does have some effect on beer pH, but it is still mostly the yeast that control it.

Now this is not to say that you can't further alter the beer pH. There are a couple of my beers that I find taste better when I bring the beer pH down to around 4.2 with a post-fermentation acid addition. But most beers don't need this.

 

[tezcatlipoca]

While the brewer can manipulate the wort pH, it is the yeast that set the beer pH. Moving the wort pH up or down does have some effect on beer pH, but it is still mostly the yeast that control it.

Now this is not to say that you can't further alter the beer pH. There are a couple of my beers that I find taste better when I bring the beer pH down to around 4.2 with a post-fermentation acid addition. But most beers don't need this.

OK, pray tell. What style beer is it that you bring down to 4.2? You use phosphoric acid?

 

[mabrungard]

American Wheat base beer for making a fruit beer is what I acidify. Since the buffering capacity of the wort has already been consumed, it doesn't take much acid to drop the pH from something like 4.5 to 4.2. I like the hint of flavor that Lactic acid provides.