I have a question that maybe has already been asked and answered in another thread: Why not use the minimal amount of bentonite that you think may work, then after it has cleared, test again for heat stability and if still not stable, do a second bentonite fining?
Fred, that is a good question. Just to be clear (chuckle chuckle), are you asking why I don't add an estimated minimum amount of bentonite to all of my bulk wine, let it settle, and then take a sample to see if that was enough and then, if not, repeat the processes until I get to the level that I feel the wine is stable?
If so, I see a couple of problems with that method.
One is time. Since the settling out process is about two weeks then this process could potentially take a while since I have no idea where the levels will end up. What if this method ends up taking 3-4 attempts at 2 weeks each X 3 white wines....I am not that patient. Also, and this probably should be a reason of it's own, each time I take the bung out and stir in bentonite and/or rack the wine I am performing an O2 exposure event.
The second reason is that I am adding the known from testing amount of bentonite to the bulk wine and then moving the containers into the 25F freezer for cold stabilization. This method will, in theory, trap the fluffy bentonite precipitate under a layer of crunchy solid tartaric crystals which should yield a more compact and less volatile layer of bad stuff that is easier to rack off and yield less wine lost in the racking process.
The third reason that comes to mind is accuracy. Using the method you have described is not a side by side analysis but a vertical analysis. Having six sample bottles sitting side by side on the counter it is very easy to see what the proper addition level should be.
The last reason is the cool factor. This is a really fun test. I feel like a real scientist doing this. Plus it is a great conversation starter...about wine...to have the samples sitting on the table when friends come over. I know this last reason is not really a reason at all but it is a great side effect.