Our Fermentation is Over

On Friday, October 23, we checked our fermentation by running a few tests using our Vinmetrica SC-300 Pro. We tested the Vinmetrica system using a wine we had on hand so we were reasonably confident that our technique could be used to test our wine. There are online videos provided by Vinmetrica that give step-by-step instructions on the following:

• How to Calibrate the Vinmetrica SC-300 Prior to Making pH and Titratable Acidity (TA) Measurements
• How to Measure the pH
• How to Take a Titratable Acidity Measurement
• How to Take an SO₂ Measurement

On this fateful day, we conducted our tests on the juice in the two kegs that had been fermenting since September 30th. Our last reading that we took on October 13th gave us a Brix reading of 9. We ran the tests on our fermentation including the Accuvin Residual Sugar Test and we found that we had the following values:

• pH = 3.15
• TA = 12.25 g/L
• SO₂ = negligible
• Residual Sugar = ~500 mg/L

We stopped the fermentation by adding potassium metabisulfite into our two kegs. I used the: Sulfite Calculator
to determine that we needed to add 1 gram of potassium metabisulfite to achieve the required 0.825 mg/L molecular sulfite level.
We had hoped to leave a little residual sugar in our wine, but the values indicated that we had far over shot our mark. We also have a lot of acidity, some might call it searingly acidic. We are hoping that our tartrate stabilization might take out some of the titratable acidity and lower the TA a little.
We are consoling ourselves with the good news.

• First, our fermentation was long and slow and we didn't run into any problems with a stuck fermentation, indicating that our fruit came in with enough food for the yeast.
• Second, we didn't have any volatile acidity (acetic acid) issues, or fingernail polish (ethyl acetate) issues, or rotten egg (hydrogen sulfide) issues.
• Third, we have approximately 5 gallons of wine from the 65 pounds of fruit that we harvested.
• And last by not least, we learned a lot and hope to apply this knowledge into configuring a working lab and getting the appropriate equipment for scaling up to a full harvest, hopefully in the near future.