White wine cold soak with pectic enzyme

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BigH

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Harvested my Brianna grapes this morning (16.8 brix, pH 3.27). Last year, I had poor juice yield with this variety, which is something it is known for. I got 3.5 gallons of juice from 8 gallons of crushed grapes in 2016. By comparison, Edelweiss gave me 3 gallons of juice from 5 gallons crushed grapes. Other than low yield, last year's Brianna turned out really good, especially for a total noob winemaker.

This year, I want to try to extract more juice without picking up any unwanted flavors. I used pectinase last year after destemming and crushing by hand, but I don't remember how long I gave it to work before pressing (poor note taking in year 1). This year, I am separating my harvest into two batches.
  1. Batch 1: Crush and destem, add sulfite, add pectin enzyme, cold soak at X degrees for N hours and then press.
  2. Batch 2: Hand destem and freeze all berries (with some SO2 mixed in). In a couple weeks, thaw, crush, add sulfite, add pectin enzyme, cold soak at the same temp and for the same time as Batch 1.

I have read that freezing berries can improve juice yield because it breaks open cell walls. The purpose of this experiment is to see how much it helps, if any when compared to using pectic enzyme by itself.

My question, what temp do I use for my cold soak and for how long?

I have read that pectin enzyme should NOT be added at the same time as k-meta, but some people feel that they can be added together. I also have a recipe that skips the k-meta and only adds the pectic enzyme after crush. The SO2 is added after the press.

Any advice is welcome. I tried searching for "white wine pectic enzyme", but most results were either talking about red wine grapes, fruit wine, or using pectic enzyme to clear haze later in the process.

H^2
 

Stressbaby

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A few thoughts
1. I believe that pectic enzyme works better at higher temps. So you might be limiting the effectiveness of the pectic by cold soaking.
2. For the cold soaks I've done I've used 35-40F.
3. You might add a third arm to your trial - usual care but simply fluff your cake after the first press and press that fluffed cake a second time. I predict this added yield will approach that of both of your other techniques for a lot less time and trouble.
 
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