Alcohol and Sugar levels

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Antonio58

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I just finished crushing and destemming my grapes, I am going to press grapes in 4 days. When should I measure for sugar and alcohol levels using my Hydrometer?
 
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Why do you think you will be ready to press in 4 days? It seems like your fermentation will take longer than that. Unless it's really warm, fermentation is about a 7-10 day process.

You use the hydrometer to know where you started, and when you approach dry. You press when you are dry or nearly dry ie when brix are 0 or below. For instance, I started Primitivo on Saturday, at Brix 23.5. Today after 3 1/2 days I'm at Brix 10.

You can only measure alcohol indirectly, making assumptions about how much of the sugar becomes alcohol. An approximation is Delta brix X 0.55.

So if brix at the start is say 24 and you end at -1, the change(delta) is 25. 25 x 0.55 = 13.75% ABV. I have found it's actually just a bit less than that but close enough.
 
Why do you check once or twice a day to monitor progress.
Speaking for myself...
When fermenting fruits, I stir twice a day to get oxygen into the must. I have my refractometer handy to get a few droplets from the stirring spoon. A free check to make sure things are kicking off. When the Brix change starts to get smaller I’ll take a true SG reading.
 
Probably more than necessary, however, the 10 minutes it takes gives me the information I need to have the confidence that things are tracking as expected.
...and to take action if things aren't on track. Also I think helpful to have as a reference for future fermentations.

I measure baseline brix and temp in juice before starting, then every day during fermentation. Here is my white pinot noir profile from last year:

ferm profile.png

Ideally I would prefer to keep white wine ferments a bit cooler - definitely below 70 F. Next time I think I'll try to rig up some sort of ice water jacket system for my kegs/carboys.
 

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