On Oct 17, 11:32 am, "Jim Hall" > wrote:
> Calculating additions at crush have always been a bit problematic for me.
> Never seem to come out right. So usually put half calc'd amount of Tartaric
> acid in for example and then check affect the next day and adjust again.
> Based on actual impact. I have a theory this year that maybe all that is
> immediately affected by this is amount of free run juice that's in the
> fermenter after crush. Let me explain by looking a batch of Cabernet
> Sauvignon wine I'm making this year.
>
> Grapes:
>
> 325 lbs of Cabernet Sauvignon + 38 lbs of Merlot
>
> Initial readings:
>
> Brix 22.5
> pH 3.53
> TA 0.52
>
> (Yep, over mature grapes that didn't reach 24 brix)
>
> Based on past experience I calculate:
>
> 31.9 gallons of must
> 26.6 gallons of wine after press made up of 17.8 gal of free run and 8.8
> gal of pressed juice
>
> Ok on to initial calculation
>
> Goal: Bring sugar level up to 23.5 Brix
>
> 1.5 oz of sugar will raise Brix in 1 gal wine 1 brix
>
> Sugar addition: 1.5 oz sugar /gal x (23.5 Brix (desired) -22.5 Brix
> (initial)) x amount of wine after pressing (26.6 gal) = 39.9 oz of sugar
> (round to 40 oz)
>
> Ok added that.. next day.. Brix 24.2 What the heck!! Ok lets back out
> how many gallons should have been used in calc then..
>
> 40 ozs sugar/(1.5 ozs (sugar/gal) x (24.2 Brix (actual) - 22.5 Brix
> (initial)) = 15.6 gal
>
> So if I had used 15.6 gal in my original formula the world would have been a
> perfect place. Ok lets go on to Tartaric acid addition
>
> I'd like to get pH down to 3.35 +/- and total acid up to 0.7 or 0.75. Plan
> on putting wine through Malolactic fermentation and that hopefully will keep
> acid and pH in desired finished wine range.. but I'm only going to add about
> half and see what happens first. I'll shoot for TA of 0.63 for starters
> then.. Here's formula..
>
> Goal: Bring TA up to 0.63
>
> 3.8 gms tartaric acid will raise TA of 1 gal wine approx 0.1:
>
> Tartaric acid addition: 3.8 gms tartaric acid/gal x (0.63 (desired TA) -
> 0.52 (initial TA)) x 10 x amount of wine after pressing (26.6 gal) = 111.3
> gms of Tartaric acid to add (round to 111.5 gms)
>
> Ok added that.. next day TA 0.73, pH 3.33.. Yikes!! that's a close call..
>
> Lets back out how many gallons should have been used in calc then to get TA
> of 0.73..!
>
> 111.5 gm tartaric/(3.8 gms (tartaric/gal) x ( 0.73 (actual TA) - 0.53
> (initial TA) x 10) = 14.6 gal
>
> Ok so based on this gallons used in these two calculations should have been
> 14.6 to 15.6 gal and that's all the wine that was affected by the additions.
> What gives here?
>
> So here's my head scratching theory... Based on past experience I'm
> predicting with prettty good accuracy free run at time of press to be 17.8
> gallons. Initially after crush, amount of free run juice is probably less
> than that and yeast will release more juice.. This is gettng close to the
> 14.6 to 15.6 gal range in backed out calculations above. Soooo, I'm
> starting to think maybe these additions are only affecting the free run
> juice in the fermenter and readings the next day are reflecting that. What
> do you think..? Does this make sense? Are we only adjusting the free run
> juice initially?

Sounds reasonable as what you're measuring at this tage is the free
run.

Pp