Raspberry Wine Settling vs Racking Technique vs Degassing

[RickD]

My must: 40oz of thawed mashed raspberries, 2lbs 12oz table sugar, 109 oz water, total volume 192 oz, starting SG 1.098, pH 3.68, TA unknown; Additives: Tannin, Pectic Enzyme, Acid Blend, Yeast Energizer, Yeast Nutrient; Yeast: Montrachet. Final SG: 0.994.

My racking technique: skim off (using sieve) and dispose of cap and as many "gross solids" (i.e., solids that my "typical" wire mesh kitchen sieve would trap) as I could. Then, pour everything into my little Big Mouth Bubbler lined with a 200 micron nylon nut milk bag. It took a surprising (to me) amount of muscle to force the wine out of that bag.



My degas technique: stirring with the wine whip for over 5 minutes produced very little results. I immediately convinced myself that my racking technique had eliminated enough excess gas.

I proceeded to add Bentonite, K-meta and K-sorbate, and rack to "carboys". (Note headspace in the 750ml bottle).



After day 8 of settling I was concerned that the level of sediment had not compacted any more than it had by day 3. I was sure I had a degas problem.



Not wanting to lose so much wine to sediment, and recalling something I had read somewhere about raising temperature to accelerate degassing, I decided to try an experiment on the bottle carboy. I placed the bottle in a pan of very warm (about 105F) water. The water level was less than half way to the top of the sediment. In less than 5 minutes the sediment began churning and outgassing, and there was a significant volumetric increase in the bottle. The volume gradually dropped back down. I know that the distance between molecules (and hence volume) increases with temperature, but to this extent at these temperatures??




Before I try this same experiment on the gallon carboy I thought I'd try to get a couple of questions answered:

1. After doing this, would It be safe to leave the wine on this sediment for another couple of days to see if the sediment will compact further, or should I just bite the bullet and rack ASAP.

2. Any ideas as to what exactly is going on here? One thought that crossed my mind was that the pressure of squeezing the wine through the bag drove more gas into solution, but remember also that I am unballasted by fact. This may become the new "normal" for me.

 

[Johnd]

@RickD , the CO2 is in solution as a result of fermentation, I doubt seriously anything you did forced more CO2 into solution. Whipping is a poor method of degassing, time is a good one, so is vacuum racking, and temps in the mid-70's help speed the process along. If it were my wine, I wouldn't heat it up out of the 70's for any reason, it can be damaged. If your gross lees are gone, and all you're working on now are the fine lees, give it lots of time to compact, it'll save you some wine loss in the end analysis. As long as you have CO2 in solution, your wine will clear slowly, when it's dissipated, it'll happen much faster.

 

[Scooter68]

Exactly as Johnd said. The only thing I might add is that when I intially rack immediately post ferment, I take the dirtest part of the wine with the lees, not the solids but the finer lees, and put them in a taller container and chill in the fridge for up to 3 days. That accelerates the lees dropping out and then you can recover more of the wine. Basicall all that wine you squeezed out of the bag could have gone into the fridge and it would have cleared up nicely. As always it's easy to tell folks what they could have, should have done but if it helps for a future batch - that's still a plus. You could still rack off the clearest portion and chill the cloudest part. Just keep your headspace down.