Should I add sugar to my grape juice?

[Pauly2275]

Hi everyone and thanks for taking the time to read my posting.

I just got back into wine making after a 5 year hiatus and bought a few pails of organic syrah from Bosa Foods this past weekend. I brought the pails home to let them warm up to the 18 to 21 degrees as recommended. By day 2 the wine had already started to ferment without me adding the yeast, so to control the fermentaion I decided to add the yeast that was provided. at that time I intended to take a specific gravity testing, but realized that since I last made wine I had lost my specific gravity tester. The soonest I could buy one was roughly 24-30 hours after the fermentation had started and was now reading 1.040. Is this a normal reading for such a short period? my concern is that the original sugar content was not high enough and I should have added it and now have no way of knowing other than going to the store and buying another pail of the juice and measuring the P.A and specific gravity before fermentaion has begun.

I guess i'm looking for some advice here in genral and wondering if it's too late to add sugar if I can determine that this particular juice does not have enough sugar in it.

Paul

 

[robie]

Sounds like the frozen pails of grapes already had the packet of yeast in them, so as soon as they warmed up, fermentation started. Lots of frozen pails now come with yeast already included.

Yes, if the temperature is high enough, the SG can drop that much that quickly. I would assume the starting SG could have been as much as 1.085, but that is just a guess of course.

You can add more sugar anytime, as long as you dissolve it well in a little warm water, then stir it in slowly and really well. Add it a little at a time, so you don't shock the yeast. If you take the SG before and after adding the sugar, you can tell how much more alcohol percentage that sugar addition will make.

Trouble is, you won't ever know for sure where the pail's SG started. However, you might be able to make a phone call to the supplier and find out pretty close. They pretty much know because they process the original juice in such bulk.

 

[buddy]

You might get a good idea of how much alcohol you have made so far by using the "boiling off method" and then use your hydrometer to see how much more potential alcohol you have. Add the two together and it will be your total potential alcohol.
The chart for the boiling off method could be found here http://web2.airmail.net/sgross/fermcalc/fermcalc_applet.html
Click on the alcohol tab and then the boiling off method tab. Fill in the required data and you are good to go.