My understanding is that yeast activity is inhibited in a low PH beer, hence the reason for pitching more yeast than normal into a pre-boil-soured beer. With this being a case, how accurate are priming sugar calculators when it comes to carbonating more acidic beers? Those of you with experience with bottle conditioning sour beers, do you add more priming sugar than you would for a more typical brew to achieve the same amount of carbonation?
The amount of priming sugar shouldn't depend on the ph. From what I understand, the reason it is sometimes necessary to add additional priming sugar in sour beers is if they are aged for long enough, (12+ months) they can lose some of the dissolved co2 that we typically see in younger beers. I think most priming sugar calculators assume something like 0.6 vol co2 already in the beer (most co2 escapes through the airlock, some is dissolved in the liquid). If the beer is very acidic it would probably be more helpful to pitch additional yeast at bottling, possibly champagne yeast, to counteract the harsh environment. My only experience is bottle conditioning a 7 month old berliner. I pitched champagne yeast and primed as I would with any normal ale and it carbed up fine. I know some people will only bottle their sours in thick belgian glass calculate for 3+ vol co2 for older sours.
Sorry I should have been more specific. I meant sour beers that have aged 12+ months in a carboy with an airlock can lose some of the 0.6 vol co2 that priming sugar calculators assume prior to bottling.
It never hurts to add little champagne yeast in this situation. If the sour is more than 1.5 months old and spent some time in the 70s-80s during or after sacc fermentation, you will likely need to use extra sugar to compensate for the loss of standard residual co2. The amount of residual co2 in your beer is determined by temperature, time, lid opening, cold crashing time, agitation, head pressure, nucleation and lunar phase. It can be as high as 0.9vols and as low as practically zero.
I've primed by adding champagne yeast and not adding yeast. When I add fresh champagne yeast they always carbonate in a timely manner and I'm able to achieve the high volumes that I'm aiming for in the end. When I don't add yeast, sometimes the beers carbonate, other times they don't. And by don't I mean they don't reach the level I was targeting. It also takes a lot longer for them to get there. What yeast are you planning on carbonating with? Brett? Sac? Brett is less affected by acidity, but it will take longer. I think it really depends on the age of the beer you're trying to carbonate. Over time the yeast concentration will drop as they slowly die. I personally think it's worth it to but a $1 or $2 package of fresh dry yeast to guarantee proper carbonation for a beer you spent so much time on. As far as losing carbonation with extended aging, my solution is to always target the high end of my priming calculator. I'd rather over carbonate a sour beer than under carbonate it.
I'm not planning on aging this beer at all. I kettle soured the wort, boiled it, then pitched two packets of rehydrated S-05. OG was 1.032. It measured 1.008 five days later, but that was a week ago. If gravity is steady, I'm planning to bottle after around 2-3 weeks as I would most ales. I don't have a PH meter, but the beer definitely tastes tart and acidic. I'm just not sure if I should be concerned about the state the yeast after 2+ weeks in that environment.
