When to harvest...

Once more, winemakers. When do I pick these ...

Cabs - Brix is 22.7 pH is 3.2 and the TA is .79

Zins - Brix is 18.2 pH is 3.4 and TA is .71 or .6 (tested with different batches of reagent.)

Weather is going to hell Monday. Rain Monday and Wednesday, more than 1/4" predicted; temps will be in the low-mid sixties as we dry out Thursday to Sunday. Probably dry and about that temp for a few days after that.

We are inclined to pick the cabs tomorrow afternoon. Really undecided on the zins - pick now and add suger, or wait a week or ten days and maybe have to add acid...? All opinions will be appreciated.

TIA

Personally, I'd pick the Zin now and add sugar at the rate that 1 cup uf sugar will raise 5 gallons of juice 1 degree brix. Keep in mind that this is for juice, not must, so 5 gallons of must after pressing is about 4 gallons of juice. The acid is right where you want it. For the Cab, you could ever wait a week on those until after the rain and it dries out.

I think the most important factor in judging harvest time is pH. Other things matter, of course, but I like to pick at pH = 3.6 or lower. Some hybrid varieties, notably Foch and Baco, should hang for a longer time in my opinion, and with those two varieties only I like to see a pH nearer 4.0 than 3.6.

My best guess is that you will have to harvest your Zin soon, and settle for less sugar than you might like. The Cab can probably hang for another week or two, which will permit the acid to drop to a more favorable level without increasing the pH too much.

Your Zin TA shouldn't vary that much, even with different batches of reagent. There is a simple way to compensate for old reagents using potassium acid phthalate and a correction factor that you might find useful.

Good luck to you.

Best

Howie, could you please enlighten me: what's the difference between juice and must? Just curious to know.
Cheers, Anders

Anders, here is what I found to be the answer as to what must is:


Must:
The combination of basic ingredients, both solid and liquid, from which wine is made. The liquid content of must is called liquor or simply juice, while the solids, when pushed to the surface by rising carbon dioxide, is called the cap. When the alcohol content reaches 8 or 9%, the liquid component is more accurately referred to as wine.

Hi Anders - Juice is the juice from fresh pressed grapes, generally to make white wine. Must is crushed and destemmed grapes that are not pressed, generally used for red wine. Generally, reds are not pressed until after fermenting on the skins, usually a week or two. It's my experience that about 20-25% of the volume in must is lost after pressing. However, some presshouses use a hot-press method, which heats up the red must to extract the color, then press it and sell it as red juice. After fresh grapes, I prefer using must.

It's my experience that about 20-25% of the volume in must is lost after pressing.

Howie, would you say that this figure represents the loss with a wine press? I hate to think what kind of number I'm getting since I don't even have a press and must press my juice out using a sieve and plastic gloves over a bucket!

Yes that's reds with a wine press. Whites are higher, as they are much harder to press.

Thanks Howie and Bob. Good to know, in particular the day my Riesling vine will start to bear grapes...
Cheers, Anders

Howie, it sounds like my answer to Anders was full of misinformation. Glad I said I was not you, and not a winemaker.

Thanks for the input Howie and Alan.

Got about 95 lbs. of fruit from our 5 zins, which are now all of 4 years old (plus maybe two before we bought them in 2 gal. containers.) I think maybe next year we read a little closer about thinning bunches right after the fruit sets! We are kind of stunned about how much friut there actually is. I read somewhere that 2-3 botttles per plant is what is expected. Not sure, but I think we might go over that on these plants this year.

Will post later with numbers from the must.