Yeast Basics: Metabolism, Pitching, and Dosage

Before you can manage yeast for flavor, you need a clear picture of what yeast is doing in the first hours of fermentation. That is where many “best practices” get overcomplicated.

You’ll cover the core yeast basics: yeast’s two metabolic modes, why it multiplies before it produces alcohol, and a practical pitching method and dosage rule you can apply immediately.

Quick summary

Two metabolisms: with oxygen vs without

Yeast has two metabolisms. With oxygen present, yeast uses oxygen to create energy and multiply. When oxygen is depleted, it switches metabolism and produces alcohol.

Why yeast multiplies before it makes alcohol

When you add yeast to grape juice or mash, oxygen is present. The yeast multiplies first. Alcohol production becomes dominant once the oxygen is used up.

There can be a benefit to that early growth: you end up with more yeast cells of different ages, which can contribute to more interesting flavors.

Pitching: why sprinkling can work best

Instead of building yeast starters over multiple days, a simpler approach: measure granulated yeast and sprinkle it on top. It claims sprinkling works best in tests because yeast rehydrates gradually, reducing yeast cell mortality compared to forcing yeast into liquid.

Dry vs wet yeast (practical handling)

Dry, granulated yeast is recommended for simplicity. There is no meaningful flavor difference between dry and wet yeast in this approach, but dry yeast is easier to measure, store, and handle.

A dosage rule of thumb (0.7 g/L)

A simple dosing rule is given: for every liter of fermentation volume, use about 0.7 grams of dry yeast. Example: a 1000-liter ferment uses about 700 grams of yeast.

Key Takeaways