Making Ice Wine

[mckenry]

Great Photo.

The Grape doesn't fall far from the vine.

 

[Tim F]

Have you got an ph/TA readings on the resultant juice? The acidity should have increased by a fair bit too.

I recall being told that figures of 10:10:10 for dessert wines (Sauternes/botrytis Semillon, etc) is a good guide to getting balance. In other words; 10B of residual sugar (~1.072), 10% alcohol, and 10g/L TA. Not sure how true that is, apparently Noble One has similiar sorts of figures (?), but 10B of residual is alot!

I haven't checked acids since I first pressed but will get my gear out on the weekend and see how it looks now! Good guideline to keep in mind, I think mine won't be quite that balanced - maybe 13% abv and 7-8Be.

Tim, I hope you can make the case swap at my place week after Easter, its just around the corner from your place.

Feel free to bring some of this wine if its ready! (I presume it will need some serious time post ferment though...!)

Nice one, didn't realise you were hosting it! If this wine has finished fermenting I'll bring a bit round for an early taste test.

 

[Tim F]

I checked TA tonight before I pitched the yeast and it is only 4.5g/l - titrated twice because that is much lower than I thought it would be. pH was 3.42 and SG 1.128. I guess that's maybe a disadvantage of freezing the juice compared to a method like semi drying or botrytis where you are actually evaporating some of the water?

Sort of makes sense if I got the freezing point depression calcs in the ball park as the freezing point of a sugar solution will be lower than a tartaric acid solution at the same strength so I guess more of the acid is frozen and removed with the water? Although commercial ice wines do have higher TA apparently so who knows. I was thinking of trying this by actually freezing and pressing whole grapes next time to get closer to how a real ice wine is made.

 

[Tim F]

I'll need to add a fair bit of acid to this to get it balanced before bottling. Wouldn't usually use an acid blend but maybe it's called for here to avoid unbalancing with too much tartaric - any opinions?

 

[Muggus]

I'll need to add a fair bit of acid to this to get it balanced before bottling. Wouldn't usually use an acid blend but maybe it's called for here to avoid unbalancing with too much tartaric - any opinions?

Typically (being from the Hunter, hot climate, etc etc) we'll have to add acid to our whites, usually at the crusher.
Tartaric on its own is usually a bit harsh and has gives the wine an "unnatural" sort of balance. To try an emulate the natural acid balance found is grapes additions of Tartaric & Malic acid are added, around about 50:50, which is closer, but not exactly spot on. Really depends on the grapes, but additions range typical range from 0.5-2g/kg of must...for ripe Hunter white anyway...

If anything, i'd conduct some sort of bench trial using blends of acids - tartaric, malic, citric...even lactic if you want, which is softer again...
Don't let the figures scare you too much, so long as the pH is below the sort of 3.3-3.4 mark, your SO2 levels should be effective.
What you're really looking for is balance, and what seems most "natural". Can be a tough task actually. Typically I got with the acid level i'm happy with, and add a bit extra...(like 0.05-0.1g/L)...because it will drop away with age.