May 2010
Newsletter
Newsletter
Filtering finished beer
I was just wondering what people think about filtering finished beer. I have a wine filter, the Bon Vino type, that takes the 5 inch square filters with the 2 holes. Normally I kill the yeast, add clearing agent and let the finished beer sit in the beer fridge for about a week. Then I filter it into a cornelius keg, and carbonate. Usually I use just 2 of the filter pads ( filter unit is set up for 3 filter pads ) and use the #2 filters. This seems to work great for me, nice clear beer. I am just curious if other brewers filter their beer, and how. Is it even necessary to bother with filtering? Does it hurt to filter the beer?, maybe causes off-flavors or strips some flavor out of the beer. What do you think?
filtering
I'm not that anal about having clear beer. I don't own a filter and I've never borrowed or rented one either. Given enough time in cold storage any beer yeast will drop right out. Chill haze will even drop out given long enough and as long as you don't disturb the keg.
Filtering itself won't hurt a beer's flavour as long as you don't use too tight of a filter. A really tight filter will actually start to strip out some flavour compounds.
There are some styles where filtering will hurt the beer, like bavarian weizens. They should be served 'mit hefe' to get the best flavour.
That said, for the first time I can remember someone entered filtered beer at our comp (this info was placed into the extra information box on our online entry system). I do remember judging one of them and it was soapy. There were other judges at the table who had judged other 'soapy' beers from other categories and they remembered that they also said they were filtered. One of them used to work in a homebrew store and he swore that it tasted like the soap the store used to clean the filter (comet and something else). In those cases there may have been a soap residue on the filter issue.
"soapy beer"
That was quite likely me, with the soapy beer. I don't think the filter was responsible for the soapy off flavor. I run sterilizer through the filter and then run fresh water through the filter before using it. After, I do run soap (dish detergent) through the filter but then also run fresh water through it. That being said, however, it could be a cause.
I am more of the opinion that the soapy off flavor is coming from the yeast and trub. I just put a batch on and it has finished secondary fermentation now, and is conditioning. I just sampled it, and it has the same off flavor. With this batch I took great pains to rack the beer off of the trub before pitching. I had read that yeast eating trub equals soapy off flavor. I am now thinking it could be because of the yeast.
I reuse the yeast from my first batch (first generation), and harvest several samples when I rack the beer from the primary to the secondary. Then I freeze the yeast samples in sterilized jars. When I use the yeast samples (second generation) I remove them from the freezer and let them thaw at room temperature and then make a yeast starter in a one gallon bottle. Then pitch into the new beer batch after cooling and trub separation.
I am going to try a longer conditioning phase with this batch to see if this will eliminate the soapy off flavor.
Anybody have any ideas on the soapy off flavor, or the yeast harvesting?
re: soapy beer
It doesn't sound like the filter is the cause but next time taste the fresh water you circulate through the filter after washing just to be sure.
Yeast eating trub doesn't = soap. Soap will come from dead yeast, ie if you leave the beer on the yeast for too long after it finishes fermentation. Once the yeast starts to die, the cell walls will rupture which releases sterols into the beer - this is responsible for the soap taste. In the early stages, dying yeast will smell and taste like flintstone vitamins.
It is true that you should try to separate your beer from the hot break (the goop that forms in the kettle) but don't panic if a bit makes it to your fermenter. Cold break, on the other hand, should be left in the fermenter. Neil (of Alley Kat) told a bunch of us a story about a brewer he used to employ who for some reason always separated the cold break before pitching the yeast. Every batch he brewed didn't attenuate (stuck fermentation).
Can't comment on your yeast harvesting regime other than to mention that freezing the yeast without a glycerine solution isn't recommended. Freezing will burst the cells which will lead to the sterol issue. Do you use glycerine to freeze your yeast? That may explain the soapy flavour too. As far as storing yeast is concerned, try storing under sterile water in the fridge or investigate slanting your yeast instead.
Mark is an expert, and he
Mark is an expert, and he definitely knows what he's talking about.
I'd like to add my two cents: You've got a ton of variables there, why don't you go back to basics and eliminate one variable at a time until you find the cause? (heck, you could brew a batch and split it into 4 parts and nail all the variables at once: fresh yeast and unfiltered, fresh yeast and filtered, harvested yeast and unfiltered, harvested yeast and filtered)
Another thing: I've left more than one batch of beer in secondary on the yeast cake for a month or more, with no detectable soapy flavours in the finished beer.