The journey to a great bottle of wine begins long before the yeast is pitched. The very first—and most critical—step is ensuring your grape must is perfectly balanced. "Must" is the term for the freshly crushed mixture of grape juice, skins, and seeds, and its initial chemistry lays the foundation for the entire winemaking process.

Rarely do grapes come in from the vineyard with the perfect natural balance of sugar, acid, and pH. By measuring and adjusting these three key parameters at the crush, you can correct any deficiencies and create the ideal environment for a clean, healthy fermentation and a delicious, stable final wine.

Start your wine off right. Shop for all your Testing Equipment and Must Additives.

For detailed calculations and a complete walkthrough of must adjustments, download our Complete 70-Page Guide to Red Winemaking.

The Three Pillars of a Balanced Must

There are three measurements you must take before you add your yeast:

• Sugar (°Brix): This determines the potential alcohol of your finished wine.
• Total Acidity (TA): This measures the quantity of acid and relates directly to how tart the wine will taste.
• pH: This measures the strength of the acid and impacts fermentation health, color stability, and the wine's resistance to spoilage.

Step 1: Adjusting Sugar (°Brix)

Your first test should be the sugar level, as any adjustments here may impact your other readings. The ideal range for most red wine musts is 22° to 25° Brix.

How to Test: Use a hydrometer or refractometer on a juice sample to get your reading.

If Your Brix is Too Low (< 22°):

The wine will be low in alcohol, thin-bodied, and potentially unstable. You'll need to add sugar, a process called chapitalization.

• What to Do: Add pure cane sugar (sucrose). A general rule is 1.5 oz of sugar per gallon of must will raise the level by 1° Brix.
• Method: Dissolve the sugar completely in a small amount of warm, chlorine-free water before stirring it thoroughly into the must.

If Your Brix is Too High (> 25°):

The potential alcohol may be so high that it will stress the yeast, leading to a stuck fermentation. You'll need to dilute the must with water.

• What to Do: Add clean, filtered water to bring the Brix down.
• Crucial Tip: The water you add must be acidified to avoid diluting the must's acidity. For every gallon of water you add, dissolve 23 grams of tartaric acid into it first.

Step 2: Adjusting Acidity (TA and pH)

Once your sugar level is correct, you can address the acidity. For red wine must, you are generally looking for a TA between 6.0 and 9.0 g/L and a pH between 3.4 and 3.65.

How to Test: Use an Acid Titration Kit for TA and a calibrated digital pH Meter for pH.

If Your Acidity is Too Low / pH is Too High:

This is the most common issue. The wine will taste flat and be susceptible to spoilage.

• What to Do: Add Tartaric Acid. Avoid "acid blend" powders.
• Method: A standard guideline is 3.8 grams of tartaric acid per gallon will raise the TA by about 1.0 g/L. Dissolve the acid in a little water before adding.

If Your Acidity is Too High / pH is Too Low:

The wine may be excessively sour.

• What to Do: For red wines, the best course of action is to wait. The secondary Malolactic Fermentation (MLF) will naturally lower the TA and raise the pH.

Conclusion

By taking the time to test and balance your must before fermentation, you are setting the stage for success. You’ll be rewarded with a healthier fermentation and a final wine that is balanced, stable, and delicious.

Get the tools you need for a perfect balance. Shop our complete selection of Testing Equipment.