High Gravity Brewing


High gravity beers also called big beers simply have more sugar than a typical beer. There is no exact threshold that makes a beer “big”, but a complete and healthy fermentation of the wort becomes more and more difficult as the O.G. creeps above 1.070. Without special measures, there is a chance the yeast will shutdown early and leave you with an overly sweet partially fermented beer that never quite lives up to its potential.

In order to get the job done, you will need a lot of healthy yeast with sufficient nutrients. Making a yeast starter becomes even more essential when brewing a high gravity beer. You may even wish to grow your starter up to a larger volume than normal. As for nutrients fortunately many of the nutrients needed by the yeast are present in malt and should generally scale as the recipe scales. If the beer you are brewing is high gravity and has a large proportion of none grain adjuncts, then you will probably want to consider the addition of some “yeast nutrient” product. The other glaring exception to the nutrients scale idea is oxygen.

Although oxidation causes off-flavors later in the fermentation, dissolved oxygen is one of the most important nutrients for yeast health early on. During the lag phase relatively little sugar is being consumed while the yeast instead gather the resources they will need for the explosive fermentation and cell division that will follow in log phase. While vigorous pouring and agitation prior to pitching might provide sufficient dissolved oxygen for a typical beer, this is unlikely to work very well for a high gravity beer. An airstone should be used to directly bubble oxygen into the wort prior to pitching the yeast.