Originally Posted by fishersfirst
So I've had a problem with fruity flavours in my beer, pretty much since I started brewing.
I've done about a dozen brews of different kinds since I started, firstly extract, then part extract and now AG.
To a lesser or greater extent in each, I'm still getting fruity flavours (even in an espresso stout!!) it's starting to really p!ss me off.
Mainly I'm getting peach/apricot type flavours.
At first I figured my fermentation temps were too high, but in the last few batches I've been really careful in fermenting within the recommended temps for each yeast type.
Esters are related to yeast. There are a few things that can influence it- stressed yeast, yeast strain, and temperature.
If you're getting unwanted esters, the first thing is to consider the yeast strain. Some strains are fruity, mostly English and Belgian strains.
The next thing is the proper pitch rate. Consult mrmalty.com to see how many packages of yeast to use in each batch, or how big of a starter to make. Proper pitch rate is crucial.
And of course temperature. A good way to avoid those unwanted esters to make sure you pitch the yeast at the proper temperature and ferment on the low end of the yeast strain's optimum range. As an example, I brewed a stout yesterday, using Denny's Favorite. I checked Wyeast's website, and this is what it says about that strain:
This terrific all-round yeast can be used for almost any beer style, and is a mainstay of one of our local homebrewers, Mr. Denny Conn. It is unique in that it produces a big mouthfeel and accentuates the malt, caramel, or fruit character of a beer without being sweet or under-attenuated..
Temperature Range: 60-70F 15-21C
Alcohol Tolerance: ABV 10%
Since the temperature range is 60-70F, ideally the yeast would be pitched at 58-60 degrees, and kept at the low end of that range throughout fermentation. I couldn't get it below 66 degrees before pitching, though. I'd like to have it cooler but my chiller didn't get it quite cool enough. I ended up pitching at 66 degrees, but it did cool down overnight.
Yeast health is really crucial to the best tasting beer, and pitching rate and pitching/fermentation temperature makes a big difference. If you're using a "clean" strain, and still getting esters it's related to yeast health.