Muscat Grape wine Acid addition, sg down by .04 in 18 hrs

[Chessdunk]

This is my second wine and the first proper grape wine. I started with very sweet black muscat grapes with strong rose petal smell. The OG of the must was 1.08, added sugar solution to take it up to 1.09. The PH however was at 4.3.

Added like 1.5 teaspoons of citric acid (due to lack of tartaric acid at that time) to a 11 ltr must and the ph was still close to 4. On day 2 the SG was at 1.08 (down from 1.09). Since the PH was still high I added 1.75 tsp of tartaric acid, this brought the ph down to 3.3. I checked today viz. day 3 and the sg had gone down pretty steeply to 1.04. When I tasted the must there was a slightly bitter taste at the back of my tongue probably due to high acidity? I panicked and added half liter sugar solution to bring the sg up to 1.05 and the volume of the must now would be 11.5 ltrs in total.

What is really happening here? Would like to know if I am going in the right direction or have I added too much acid? I am hoping that the yeast consume the Citric acid and my acidity will probably get down a tad... which would be perfect... If that does not work I might probably add some water to reduce the acidity. I am assuming that my ABV would be somewhere around 13.5% based on my calculation without further dilution / topping up.

Wanted to check if I am going in the right direction or should I do something different? What is the reason for the bitterness?

 

[salcoco]

I would guess the bitterness is from the tannin in the skins of the grapes. I would add yeast nutrient, something like Fermaid-k. roughly 1 gram per 4 liters. let it ferment to completeness. rack a number of times to make sure it clears then do taste test. acid can be added later or balanced with sugar syrup.
what yeast are you using?

 

[Chessdunk]

Thanks Salcoco. I used rc 212 with 2grams dap and 1gram nutrients. Used a homemade wheat malt solution as my starter for the extra kick. Total volume is now 11.5 ltrs. I wanted a slow fermentation for color extraction but its day 2 and already down to 1.04 from 1.09 starting gravity. Trying to keep the temp at 21 to 23c

Fermentation is pretty active and the sourness is not too high after the sugar addition. What is the reason for the. 04 sg drop in a day? After the tartaric addition.

 

[salcoco]

fermentation will drop the sg pretty quickly. if you want slower ferment need to keep it cooler , around 65 degrees F. sorry don't have conversion table handy.

 

[Chessdunk]

Oh!! I thought 21 to 24 was the ideal temperature. I have transferred to secondary at 1.02... there is a light bitterness due to the tannins. But that doesn't seem harsh to me. The sourness too seems to have gone down... maybe the yeasties feasted on all that acid? Plan to wait for 15 days or so and do my first transfer. Trying to keep the wine at 20 to 21 c during the secondary. Hope this is good?!

 

[salcoco]

the yeast eat sugar not acid. have you pressed the grapes since you state that you are now in secondary?

 

[JohnT]

Just to be retentive here for a minute....

I believe that grape fermentation will cause a decrease in your acid level (although only very slightly).

 

[Chessdunk]

Yes I have pressed. I have about 8 liters from a 11 ltr must. It is foaming and fermenting I the secondary.

The acid level is definitely down, maybe because I diluted with half liter sugar solution and Wuthering the effect of fermentation It tasted perfect when I transfered. Got to wait and see.