Does Bottle Conditioning affect ABV?

Not in a meaningful amount. The amount of sugar necessary to create fermentation is very low. Off the top of my head I seem to recall natural carbonation adds like 0.05% ABV.

 

It depends on the concentration of the priming sugar that you add to the beer. If you dissolve the sugar in 5 gallons of water and add it to 5 gallons of beer, obviously, you'll cut the ABV by almost half. If you just add the sugar directly to the beer without dissolving it in anything, then the ABV will go up a bit (probably in the 0.1-0.2% range, as a guess off the top of my head).

 

Keep in mind the yeast has a finite attenuation capability. At some point it will no longer metabolize sugars left in the beer. If it didn't work that way, many beers would be thin bitter alcoholic water.

 

It doesn't get more alcoholic if thats your question. There's only enough sugar added for the yeast to carb the beer in the bottle. Once the sugar is done, it's done and the yeast goes dormant. It doesn't get cranked up again to do much in the way of alcohol production.

 

if there was a significant amount of fermentation going on the bottle would explode

 

Brewing yeast--saccharomyces--cannot consume all sugars in beer and cannot always ferment a beer until all sugars are depleted. Every strain has certain kinds of sugars it can ferment and an attenuation limit where it will stop fermenting sugar after so much has been consumed.

The bottle carbonation process is a controlled fermentation of simple sugars. Additional sugar is added to the beer for that purpose. The yeast consume the priming sugar and then stop fermenting. It only takes days for the priming sugar to be consumed (in most cases) and then a few more days for the extra CO2 to absorb into the beer. Beyond the priming sugar introduced for carbonation there should not be additional fermentation in the bottle. Further conditioning should only be the yeast continuing to clean up fermentation byproducts and various non-fermentation reactions between the contents of the beer and any oxygen picked up in packaging.

Some strains, and I'm thinking saison strains here, are notorious for finding something to eat after packaging due to various reasons and there is unintended additional fermentation in the bottle. That often happens because the yeast were not given proper treatment to finish fermentation before the packaging process began or the beer was packaged too early (or both). Any beer with brett that is not completely dried out will continue to ferment in the bottle because brett eats almost anything and it will produce CO2 by fermenting residual sugars and starches. Other food sources can be fermented but do not always produce CO2 as a byproduct.

 

When bottling my home brew, especially highly carbonated saisons, the abv goes up about .2 - .4 % abv. But once its finished bottle conditioning, further aging won't cause a rise in abv if all the sugars have been converted.

 

Umm. Bottle bombs.

 

Maybe, consistency between batches is one of those things that's tough to master. It's dependent on many variables. That's one of the things you gotta give to the macros, they turn out very consistent brews. It may not be all that good, but it is consistent.

 

I don't think I've seen a stout that was bottle conditioned. Do they actually exist?

 

On the other hand, their consistent ABV is done by the amount of water they add to the beer, isn't it? So not really terribly impressive. I could do the same thing if I had all the fancy equipment to determine alcohol content. I'd say what is more impressive is consistent fermentation characteristics, or their yeast handling.

 

The bottle conditioning process doesn't continue on for years, the yeast consume the small amount of sugar thats added to the bottle for priming over the course of a few weeks and then the process stops. If it continued on indefinitely not only would the beer become more alcoholic, but the bottle would also explode.

 

Yes, there are plenty of bottle conditioned stouts.

 

such as?

 

Pretty sure that assumption is the best answer

 

In the US, under TTB regulations, such labeling would be prohibited:

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https://www.google.com/#q=commercial+bottle+conditioned+stouts