Friday, March 26, 2010

Top Cropping Yeast from a Carboy

Sometimes I'm a cheapskate.  I know it's not a huge expense to get a new vial of yeast to brew, but I see no reason not to reuse yeast when possible.  When harvesting yeast from a batch of beer, there's many ways to do it.  You can pitch a new batch of wort on top of the yeast cake from a previous batch.  I've done this a few times and it works real well and you get a good fermentation, but I'm always a bit skeptical of pitching on top of the old trub.  I'm just afraid that all the old junk will give some off flavors. Plus I have read that the best yeast to use if you are going to harvest, is the top yeast in the krauesen.  If you are using a bucket, that yeast is easy to spoon off., but fermenting in a carboy makes it difficult to get at the yeast.

So I rigged up a system to top crop the yeast in a carboy using a racking cane, some tubing, a jar, and an airlock.  It works like a blow-off tube, but doesn't blow off into a sanitizer solution to be discarded.  Instead, you blow off fresh yeast into a sanitized container that is fitted with an airlock so you can keep the yeast.  The idea is to insert the racking cane into the carboy so the bottom is just above the top of the fermenting beer, where the foamy krausen will be.  The cane is connected to tubing that runs down into a sanitized jar fitted with an airlock. So once fermentation starts, the pressure will  push the foam out through the racking cane and down into that collection jar.  I also like to collect a little beer into the jar as well. To do this just push the racking cane down into the carboy further.

 I've also seen people use this method with a 1000ml Erlenmeyer flask fitted with a two port carboy cap.  But like I said above, I'm thrifty.  So for this batch at least, I used what I had on hand.  Here is a photo of fresh new top cropped yeast as it is collected in the sanitized jar:

 After collecting enough yeast,  the racking cane is removed from the carboy and replaced with an airlock.  Then if I'm using the yeast within a few days, I just put some plastic wrap over the top of the jar with a rubber band and put it in the refrigerator. Or for slightly longer storage, I bottle it in a sanitized bottle.

The most I've ever reused yeast is three batches, and haven't had any problems yet.  If I had more sanitary conditions, better temperature control, and better equipment, it would be possible to use it for more batches.  I think for now three or four generations is about all I want to risk before mutations and infections occur.

I upgraded my collection equipment so now it's not quite as hillbilly.  I bought an Erlenmeyer flask and some better carboy caps (5Gallon cap fits on the Erlynmeyer and 6Gallon cap for the Better Bottle).  I also bought a PET racking cane and cut it a bit shorter so the overall height of the setup isn't as high.  Mainly a space and aesthetic issue.  But overall, I think this system is more solid and with the better fittings, should be no leaks in the system.

So after one night my Pumpkin Porter fermentation filled the flask.  I got lucky and was able to switch out the flask with a blow-ff bucket before the flask totally overflowed as well.  Here is a picture of a 1000ml flask filled with fresh bubbly White Labs Burton Ale yeast topcropped from my Pumpkin Porter!

Wednesday, March 24, 2010

Farmhouse Ale Experiment

A few weeks ago a had the pleasure of drinking a bottle of Lost Abbey's Avant Garde farmhouse ale. I really enjoyed this beer, and noticed quite a bit of sediment at the bottom of the bottle. Thought it would be interesting to see if I could harvest the yeast from the bottle and brew something up with it.The big question, which I still don't know the answer to, is whether Lost Abbey uses the same yeast to bottle with as they use for primary fermentation.  Probably not, but so what.  I tried it anyway.

When I poured the beer, I was careful to not disturb the sediment and left about a half inch of beer in the bottle as well.  Then I put the cork back in and set it in the refrigerator for a few days until I had some time to brew up a starter.  When I finally had time, I got the bottle from the fridge and let it sit out at room temperature for a few hours.  Then I brewed up a small wort using a couple pints of water, about 1 1/2 cups light dry malt extract, some yeast nutrient and a few hop pellets.  Once cooled I poured this into my sterilized bottle and shook it for a few minutes to aerate.  Then I swirled the sediment around in the Lost Abbey bottle, popped the cork out and poured the sediment into my starter bottle. On went the airlock and all was set to see what would happen in the next few hours(hopefully), or days.

Next morning I took a peek out in the garage:  nothing happening.  A few days pass, and no bubbles from the airlock, and no foam in the bottle.  I check the temperature and it's about 64 degrees.  The Lost Abbey website says the yeast for this beer is a house lager strain that they use at ale temperature.  So I figured 64 was probably ok.  A few more days went by and still nothing.  I figured at this point the experiment failed, and went about other things.

A couple more days went by, and as I was fishing a beer out of the garage fridge, I noticed out of the corner of my eye that there was some white forming in the yeast starter over in the area I ferment my beer.  I thought to myself, "oh great the mold is setting in".  I didn't want to mess with it, so I left it.  Then the next morning I went out to dump the starter and to my surprise I had a fermentation going!  The white stuff I had barely looked at before was actually the first foamy bubbles as the yeast finally started getting active.  I checked the temperature, and it was now about 68 degrees in my little cave/corner in the garage.  So maybe those extra few degrees where what the yeast needed to get a kick start?   Here are a couple photos of the yeast starter:

All looked good, so I decided to go forward with the experiment.  I brewed up a small 3 gallon batch of wort and pitched this yeast starter into it.  This time primary fermentation started up within an hour or two and is now slowing down on its third day.  The krausen looks real good, and the smell coming from the airlock smells like beer.  Maybe there is a little sulfury/banana smell?  Hard to tell.  But since this is supposedly a lager yeast I would expect it to smell quite a bit different from the Cal and American Ale yeast I usually use.

So I'm keeping my fingers crossed that this will be drinkable and actually taste good.  I plan to condition it for a month or so then bottle it and maybe taste it after another month in the bottle.  I'll update the post when I try the beer.  Cheers!