I’d appreciate your feedback about this idea: I have a 5 gallon mead that started at 1.100, and is currently at .998, using K1-V116. I’m wondering if I added 96 oz of Vintner’s Harvest Elderberry Juice to the bottling bucket, re-yeast and bottle. Is this a bad idea, either for the bottle bomb possibilities, or from the flavor side? I made a cyser that I added a couple of cans of apple juice at bottling, which worked out pretty well. This seems to be a similar practice. What do you think?
You can do this, but it will probably give your more sediment in your bottles, and you won’t be able to adjust the flavor it it doesn’t turn out the way you want, whereas if you add things into the storage container, you can tweak things before bottling/carbonating things. However, if you want to do it as you propose, it can certainly work. You just need to be very careful in measuring the gravity - it is helpful to have a fine scale hydrometer to work with for this sort of thing.
If you are bottling in beer bottles, you won’t want more than about 3.5 volumes of CO2 as a maximum. That would be adding about 5.25 gravity points. So you can mix in the elderberry or any juice as long as you don’t raise the gravity by more than about 5 gravity points, you’ll probably be OK in a beer bottle. Getting an exact reading becomes important and that is why I recommend the narrow range hydrometer - there can be a lot of error in reading a standard one.
If you use Champagne bottles, you can probably go up to 9 gravity points, but I wouldn’t recommend more.