I have been researching this on some blogs and have seen info on this topic but not an answer to this question. I have brewed a 10.6% Belgian tripel with an FG of 1.02 about 6 weeks ago (secondaryed at 2 weeks). The yeast I used is Wyeast Belgian Abby which is good to about 12%. I have read that due to the higher ABV I should think about repitching yeast a day or two ahead of time. I have seen a lot of suggestions to use champange yeast due to its alcohol tolerance. My question is this: If I use a different yeast shouldn't I be worried that the new yeast may consume the residual sugar as well as the bottling sugar, thus not only changing my flavor profile but making bombs as well?
My plan is to siphon off about a cup of the beer into a beer bottle and add some sugar and cover it with a balloon to see if the yeast is still in suspension. Once I bottle it for good I plan on letting it sit for a good 2 mo in the bottle, so even if it is really slow to carbonate I would think I should be good. Any thoughts on this couse of action, while I'm at it? Thanks.
Okay first off I don't really think you are going to have a big problem here. I have bottled pretty high alcohol conentration beers, and as long as they haven't been conditioning for quite some time (think 6 months to a year) there will still be viable yeast in the fermenter. When you transfer into a bottling bucket you can stir up a little of the yeast cake to make sure you will have enough yeast (at least one of those little buggers ought to be alive) to carbonate. Carbonation may be slow but it reduces the chance of contamination by introducing something new the beer. I have had a bad experience with adding new yeast to a nearly 6 month fermented lager. It wasn't the new yeast but the new bacteria that caused a major catastrophe.
The scientist in me also wants to impart some advice for doing experiments. Experimenting is a good way to learn new things, but it must be done using the scientific method. Here are a couple of suggestions that would make your experiment useful. First, you don't have a control for what a normal carbonation event would look like, the expansion of the ballon in a normal beer as it carbonates. Therefore you don't have anything to compare your test against. Second, if you want to do a test I suggest doing them in threes. Gives you a much more meaningful data. And you wouldn't necessarily need to use a large bottle, although I am not exactly sure what you would need to do to extrapolate the data back to a full bottle.
There are plenty of things that can go wrong in your balloon test, so while it will be fun to do, I'm not sure how to interpret the results. Any contamination that occurs will result in a false positive, and any leaking in the cup or balloon will result in a false negative.
There is a strain of dry Belgian yeast that is made to be specifically tolorant of alocol, while not being a great attenuator. This makes it a fantastic bottling strain, which is it's primary purpose. The yeast is Safale T-58 and is readily available at most brew shops and definitely easy to get online. I'd suggest adding a packet of it to your brew a day before bottling. Or make a slurry with it and add it when you rack into the bottling bucket.