Other ways of enhancing ester production is by brewing high gravity beers, long maturation times, higher fermentation temperatures, and increasing attenuation limit. Conversely, if you wish to limit ester production (without changing yeast strains, that is), then you can increase wort aeration, brew lower gravity, decrease the attenuation limit, lower fermentation temperatures, or perhaps keep some over-pressure on the fermentation. There also tends to be variations in ester production when comparing ale and lager strains, although production variables like those mentioned above (and particularly yeast health and fermentation temperatures) can sometimes overpower these inherent differences. All things being equal, ales tend to have ester levels up to about 80ppm while lagers usually don’t get much above about 60ppm. That being said, ester production is very nuanced and complicated, so finding the right balance of production variables may be easier said than done. Of course, the usual flavor caveats apply to esters: there are guidelines for ester levels depending on beer style, but it’s ultimately up to the brewer whether they belong there and at what level.
