First what would you recommend to address the must as it is now? I can cold crash, and I've got sparkeloid and other clearing agents. Maybe just hit it with a ton of PE when I rack?
Secondly, is there anything I could have done to prevent this? Pull the brew bags with skins sooner? Avoid such a fast and hot ferment next time? Attached photo for reference
Probably all the above
. To address terminology...COLD CRASH is a term used for making beer and not wine. Although, the process of cooling down the ferment/must/wort us used and physics is used, >cold stabilization< is more appropriate
. The cold stabilization process is directed at multiple changes in wine. Protein stabilizing and acidity are addressed for wine making and not for beer. (an entirely different conversation)
There are multiple ways to achieve clearing of wine. Generally, the two that need to be considered, particulates and proteins. Particulates are "relatively" easy: a) Time is your friend. b) Two part fining works well, but understand it works on the positive and negative charges of ions of the particulates. I use Kieselsol & Chitosan, but there other combinations that work well also. c) Cold stabilizing helps. That works on the physics principle of difference of densities making particles seem heavier in relation to the liquid. d) Filtering can be used, but only for polishing a clear wine.
Proteins are a different and a bear to correct. They affect clarity by the long chain molecules diffusing the light passing through the wine. Breaking the long chain molecules into shorter ones is where pectic enzyme (PE) comes in. PE works best at warmer temperatures, roughly around 80-85*F but is less effective at cooler temperatures (it works, just takes longer). PE is also less effective in finished wine when alcohol is present. So hitting it "with a ton of PE" can help, but using it post fermentation is in for the long haul (months). Bentonite can be used for proteins, but it's a two edge sword. Too much will strip flavor and color, too little starts to address the issue but gives the impression "it doesn't work". Another sharp edge of Bentonite is it affects PE, so using both together essentially cancel each other- and back to the "it doesn't work" impression. Bentonite can be used for particulate clearing as part of the other products mentioned earlier.
The prevention part can be decided pre-ferment. But it depends on what you want to address. Both PE and Bentonite can be used on the front end of fermentation, but not both at the same time.
Color between pre ferment and post ferment is another area for discussion. Keeping color gets even more technical.
What can be done is keep tabs on pectin while using methods to reduce it. (If not reduced, it will wind up in the bottle as brown flakes after a time
. Ask me how I know) Doing that is using a simple test of mixing a 3;1 ratio of methylated spirits to wine/must. If pectin is present, a snotty white goo will form. I have attached photos of a comparison for reference. The photo on the left is plum wine before fermenting. The photo on the right is the same wine. PE was added pre ferment, racked, K&C added, cleared for about a month, and a dose of bentonite added and let settle for another month. The photo was taken after all of those treatments. Through all of that, I've learned to adjust my methods for more effective use of the products. Yes, plums have LOTS of pectin.
So, as with all wine, learning curves get pretty steep. The really hard part is separating rumors from best practices. Finding supporting >documented< papers to support best practices requires lots of reading. The Scott Labs website is a start. Multiple books are available as well from well known authors.