Fermenters Forum

Day One
3 pounds previously frozen raspberries
2 pts spring water
1/2 tsp acid blend
1/2 tsp pectic enzyme
1/16 tsp potassium metabisulfate

Let sit for eight hours to make a fruit liquor/slurry. This allowed pectic enzymes to break down fruit before adding yeast nutrient, then added:

1 tsp nutrient
5 pts spring water
5 c sugar to reach SG 1.095

3.22 pH
0.8% Acid
1.095 SG

24 HOURS LATER
Added 1/2 tsp Red Star Pasteur Red yeast

FIVE DAYS AFTER ADDING YEAST
Still at 1.030. Poured into sanitized secondary.

Saved a pint and put into the refrigerator to add back at a later racking.

A COUPLE MONTHS LATER
Racked off lees.

December 12
Racked. Added 2 1/2T raspberry extract, 1/8 tsp (0.75 g) potassium bicarbonate (to reduce tartness slightly) and topped with 1 c of the leftover primary must that I had refrigerated.

March 15
Good strong raspberry flavor, tart. ph 3.47, acid tested at 1.0%. Still need to reduce acid.

(Winemakers use pH as a way to measure ripeness in relation to acidity. Low pH wines will taste tart and crisp, while higher pH wines are more susceptible to bacterial growth. Most wine pH's fall around 3 or 4; about 3.0 to 3.4 is desirable for white wines, while about 3.3 to 3.6 is best for reds.)

Potassium Bicarbonate can be used by winemakers in the winemaking process to reduce acid in wine. It can be added at a rate of 1 1/3 tsp (or 3.4 g) per gallon prior to fining to reduce acid by 0.1% Wines that use potassium bicarbonate to lower acidity can then cold stabilize their wines and rack off any "wine crystals" that may form. Potassium bicarbonate is recommended when making only minor acidity adjustments in wine. It is not recommended to use to reduce acid more that 0.3% or with wines higher than pH 3.5.

Racked and added 2 1/2 tsp potassium bicarbonate. Racked and added 3 1/2 tsp potassium bicarbonate. ph is now 4.5, a bit higher than it should be at 3.6 max for a red. We'll airlock and test again in a week.

I thought I added too much potassium bicarbonate because of the higher ph, but the titration test, which is supposed to be more accurate, is still showing around 0.75% acid, which should be plenty.

Bottled December 2018
Drew up some wine and added 1/16 tsp potassium metabisulfite to kill off any yeast and max 1/2 tsp wine conditioner potassium sorbate/gal, the minimum to stabilize, but not sweeten.

Bottled and degassed each bottle twice with a plunger. Drew off a bunch of CO2.

Tested ph at 4.26.