Other SG With Grape Skins

[GaDawg]

I take the beginning SG and take the 2nd SP the next day, and it is always higher. So I know that the grape skins increase the SP. Over say 7 to 10 days I squeeze the skins a couple times a day. I think the act of squeezing the skins add to the SG and the alcohol over that time, but about how much? Do you guys think the ABV goes up 1% or 2%? What do ya'll think?

 

[AZMDTed]

My experience with WE Eclipse packs is that the initial SG will rise from about 1.085 to 1.090 or another couple points. Assuming the same ending SG after fermentation, wine ABV calculation shows that it will increase alcohol from 12.91% to 13.59%. If it goes up a bit more to 1.092 then you'll end at 13.86%. Since many of their big reds are rated at 14% and the rounding error in wine Alcohol content level is huge, I consider this to mean that that's about all you're going to get.

I've spoken to WE about the effect of the grape pack and they said to give it about 12 hours and then take the SG reading when it should be about it's highest. I don't know if future squeezing will increase the SG or just make sure that you get it all. That's tough to tell because by that time the yeasties are doing there thing and reducing the sugar.

What did you get for the initial and next day SG readings?

 

[sour_grapes]

I do keep track of this. I take a reading before adding the grape pack, then keep monitoring the SG until it reaches a maximum.

For me, a "typical" increase in the SG after adding the grape pack (for Eclipse and CC Showcase kits) is about 0.016 to 0.018 points, which is about 2 to 2.4%. WE Selection kits have been more like 0.012 to 0.014 (1.6 to 1.8%). Of course, it could be the case that more sugars are released after the SG starts to fall, depending on how fast the fermentation takes off.

The largest increase I ever saw was 0.021 points (2.75%). This was on a CC Showcase Amarone. I used BM45, which is a relatively slow-starting fermenter, which perhaps gave more time to allow the sugars to be released before the yeast started decreasing the SG via fermentation.

 

[wineh]

I squeeze the heck out of the grapeskin pack to get the sugar out of them. On Selection kits my sg readings are 1.079 to 1.09 ish, and the Eclipse kits get 1.08 to 1.098 ish.. Getting the final sg near .99 gets an ABV of around 14% (Eclipse) like suggested.

 

[DoctorCAD]

Remember, SG is not only measuring sugar (and ABV because of it) but is measuring everything that makes the liquid thicker than water. Squeezing the grape pack adds solids in many forms, sugars, tannins, tiny chunks of pulp, bug parts, cat fur, bird droppings, stems and seeds etc.

I guess that's why it's called P(otential)A(lcohol) and not G(uarranteed)A(lcohol)>

 

[Boatboy24]

In an ideal scenario, I mix up a kit with skins first thing in the morning and really try to stir well. I'll then revisit and stir a few times over the next several hours - maybe all day long, if the schedule allows. Then I'll pitch the yeast. I take an SG reading as much as every few hours (until it starts to drop) and use the highest reading as my starting point. This is more successful on WS and CC Showcase kits than it is on WE kits. For some reason, the WE kits seem slow to give up the sugars.

 

[AZMDTed]

In an ideal scenario, I mix up a kit with skins first thing in the morning and really try to stir well. I'll then revisit and stir a few times over the next several hours - maybe all day long, if the schedule allows. Then I'll pitch the yeast. I take an SG reading as much as every few hours (until it starts to drop) and use the highest reading as my starting point. This is more successful on WS and CC Showcase kits than it is on WE kits. For some reason, the WE kits seem slow to give up the sugars.

How much of a change do you usually see in SG from the initial reading till it starts to fall, and how long does it take till you get to the start to fall point?

 

[Boatboy24]

How much of a change do you usually see in SG from the initial reading till it starts to fall, and how long does it take till you get to the start to fall point?

It varies, and I don't permanently record it, so I'm not sure. In my 'official' log, I only record the highest.

 

[GaDawg]

Thanks guys, so I can guesstimate about 2%

 

[richmke]

There is about 1/3 cup of sugar in a pound of raisins (proxy for grape skins).

There is about 3 pounds of raisins in a 2 liter grape pack.

1 cup of sugar (3 pounds of raisins) will raise the SG of 6 gallons by about 0.015.