Use your favorite liquid yeast strain for flavor and aroma, then use a neutral yeast strain to shore up your pitching rate.

Pitching rate, the number of yeast cells used to inoculate a given volume of wort, influences several things in the brewing process. Higher pitching rates lead to faster fermentations — they start faster and finish faster. Higher pitching rates also lead to finishing gravities closer to what is predicted by a forced fermentation test. In other words, the yeast utilize all the carbohydrates that they can. In contrast, in severely underpitched beers, the yeast may quit early and leave fermentable carbohydrates behind, resulting in a higher final gravity (FG). Low pitching rates are frequently the cause of stalled or stuck fermentations.

For “characterful” yeast strains that produce plenty of fermentation byproducts, higher pitching rates are associated with “cleaner” beers. Some Belgian ale strains produce an estery, “spicy” aroma when slightly underpitched, but produce a cleaner beer when pitched at a higher rate (to a well-aerated wort). Temperature also plays a major role, with higher temperatures leading to more fermentation byproducts.

This is true of White Labs WLP530 (Abbey Ale) and Wyeast 3787 (Trappist High Gravity) yeast — larger than optimal pitches, thorough aeration, and low temperatures (within the usual ale fermentation range) lead to clean fermentations. It is also true that the “banana ester” level in German hefe-weizens can be manipulated this way.

Homebrewers who are concerned about their pitching rate generally consult a pitching rate calculator, then make a yeast starter of the suggested volume. However, if your brewday arrives and you haven’t made a starter, there is a way to “cheat” that may come in handy occasionally.

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