Ask Mr. Wizard

Should I Condition a Weizenbock?

TroubleShooting

Brian Trivitt • Springfield, Missouri  asks,
Q

I brewed a weizenbock with an OG of 1.070 and transferred it into secondary conditioning where it has been ever since at room temperature. I plan to keg it soon, but I was wondering, should cold I condition it first? For hefeweizens and weizenbocks, a certain amount of yeast left in suspension is desirable for the style, right? Finally, is there anything else I need to consider before kegging it, as I know hefeweizens and weizenbocks are generally bottle conditioned.

A

I think the key with kegging unfiltered beers where you really do want haze and some yeast in the keg is in haze control. If you simply rack cloudy beer from the primary into a keg, force-carbonate using a proven method, and tap the beer, say, three days after racking you are likely to be pretty unhappy with the results. My guess is that the first several pours from the keg will be in the form of yeast slurry, which is probably not what you want in your pretty weizen glass. You will eventually blow the yeast from the bottom of the keg and net what you seek, but then the next time you pour from this keg you may have a few more pours of yeast slurry.

Haze control is attempting to balance the impossible. You want a beer that is cloudy and has some yeast in suspension, but you don’t want yeast slurry pouring from your keg. Haze control at Springfield Brewing begins for our wheat beers with wheat malt selection. I have empirically found a type of malted wheat that works quite well for our brews and it is important to use malt that is able to result in cloudy beer because not all haze is from yeast. We also use a little raw wheat for our American-style unfiltered wheat (and of course we skip this addition when brewing weizens.)

The next major step in haze control is what to do after fermentation. This really depends on the yeast strain. Most weizen beer yeasts are true top cropping yeasts and if you have the ability to skim a fermenter or use a vacuum skimmer (check out “Brewing with a Vacuum Cleaner” in the June 1996 issue of BYO) you will be able to remove much of the dense yeast from the top of the fermenter after fermentation is complete. But since most weizen yeast have fairly low flocculation characteristics there will still be a fair amount of yeast in the beer giving a nice haze.

Our American-style wheat is fermented using WLP001 from White Labs. This yeast is fairly flocculent so it is important to allow flocculation to occur before racking. We cool our unfiltered wheat down to 32 °F (0 °C) and hold it for two days before racking, which knocks the bulk of the yeast from solution. It helps if you have some way of dealing with yeast that settles in your keg. We put a ring around the outlet of our serving tanks to prevent yeast that settles from being pulled out into our draft lines since most people prefer drinking beer to yeast sediment. If you use Cornelius kegs you can trim the outlet tube by about a half-inch (1.2 cm) to limit yeast carry-over.

Another approach is to forget about trying to remove yeast before racking and to rack the beer after fermentation is complete and the beer has had time for diacetyl and acetaldehyde reduction. This is where your brews are right now. You could simply rack the beer warm, cool it down in a refrigerator and then carbonate. The trick to prevent half-liter yeast slurry pours is to give your keg a careful “rock” before each tapping session. This moves the yeast off of the bottom of the keg and makes for a nice cloudy pour minus the little yeast clumps that may appear otherwise. There are several commercial brewers of unfiltered wheat beers who suggest keg rocking to draft accounts in order to maintain consistent haze.

Response by Ashton Lewis.