Bottle Conditioning an Eisbock

[SigsNanoBrew]

I brewed a Kulmbacher Reichelbrau Eisbock clone using the methods and recipe provided here:

http://byo.com/stories/beer-styles/item/593-eisbock-brew-the-beer-money-cant-buy

I removed about 10% of the volume as ice. Estimated ABV is about 11.5% after ice removal. My starting gravity was 1.090 and my FG is 1.016 (after ice removal.) I have lagered the beer at near freezing and am ready to bottle. The instructions state:

"Priming sugar should not be necessary because the final gravity is at least the post-fermentation 3° Plato (after concentration)."

So I tried 2 test bottles. In one I added no priming sugar and to the other I added 3 Brewer's Best Conditioning Tabs. I also re-inoculated with yeast by adding a few grains of Lallemand CBC-1 Cask & Bottle Conditioned Beer Yeast to each bottle. "CBC-1 yeast referments beers up to 12-14% ABV" according to Lallemand. But after 2 weeks at room temperature, neither of the bottles were carbonated--only a slight hissing sound when opened. My beers have always carbonated easily within 2 weeks using this method, however they are usually in the 5-7% ABV range.

My question is two-fold:
1. How much if any priming sugar to add? The instructions state that "priming sugar should not be necessary". I have never heard this advice before for any other beer style, and I am afraid that without priming sugar, the bottles will never achieve sufficient carbonation. But I am also afraid of bottle bombs if I add too much sugar on top of the residual sugar already present after concentration.

2. How long should carbonation take? Clearly 2 weeks was not enough but how long is necessary to achieve completion?

So should I run more tests, or bottle the batch? If so, how much sugar to add, if any? I don't want to run tests only to wait a month and find they are still flat. I need a tried-and-true method. If you have specific experience with bottle conditioning an Eisbock please tell me how you accomplished it. Thanks.

 

[StoneHands]

I don't have the eisbock experience you're looking for, but I have bottle conditioned a few doppelbocks.
1. For a fully attenuated eisbock (and it needed to be fully attenuated before eising), there is no residual sugar to allow the carbonation to happen, so I'm a little surprised by those directions. I would add your typical priming sugar for your desired carb level and carry on.
2. This is where you'll see a difference. The last doppel I bottle conditioned took about 4 months to fully carb. I did not add any additional yeast at bottling time. I think with your higher alcohol environment, it takes a bit longer to achieve that carb you're looking for. Adding a small amount of yeast slurry - and I would go with a slurry instead of dry yeast directly to the bottling bucket (or if you do, rehydrate first) - will probably decrease the amount of time that it takes to carb. I like to wait though, you get the nice dark malt flavors and aromas if you wait. A month or two minimum though IMO.

 

[SigsNanoBrew]

Thanks, I was thinking along those same lines, only that there may be some residual sugar left because the beer is somewhat sweet (and pretty tasty even at this early stage and flat). I did not rehydrate the yeast in my test bottles, and only used a few dry grains. I am planning to use a bit more priming yeast next time, rehydrate first and pitch the slurry. (I have conditioned with and without re-pitching yeast, and re-pitching definitely speeds up the bottle carb time--from 3-6 weeks down to 1-2 weeks in a normal beer.)

I am still concerned that after concentrating there may be enough free sugars present to affect the priming calculation. Perhaps some sugars that did not ferment at the cold temps used for this beer, and at the ~10.5% alcohol level before icing, may still ferment at the higher room temp bottle conditioning environment with the CBC-1 which can go as high as 14%. Just to be sure I ordered a residual sugar test kit (which only measures fermentable sugars). This should tell me decisively whether there is any available sugar remaining or not. Once I have that info I'll have a better idea about how much priming sugar to add. I don't want to leave anything to chance, since the cold weather is ending and I won't have the opportunity to do this again until next winter and I don't want to risk making bottle bombs.

For anyone that is interested, Lallemand recommends re-pitching with 10g yeast per hl of beer, which is about 2 grams per 5 gallon batch, or 3/4 teaspoon. Roughly 1/8 tsp per gallon or about a droplet in a bottle.

I'll report back my findings after taking the residual sugar test.

I don't have the eisbock experience you're looking for, but I have bottle conditioned a few doppelbocks.
1. For a fully attenuated eisbock (and it needed to be fully attenuated before eising), there is no residual sugar to allow the carbonation to happen, so I'm a little surprised by those directions. I would add your typical priming sugar for your desired carb level and carry on.
2. This is where you'll see a difference. The last doppel I bottle conditioned took about 4 months to fully carb. I did not add any additional yeast at bottling time. I think with your higher alcohol environment, it takes a bit longer to achieve that carb you're looking for. Adding a small amount of yeast slurry - and I would go with a slurry instead of dry yeast directly to the bottling bucket (or if you do, rehydrate first) - will probably decrease the amount of time that it takes to carb. I like to wait though, you get the nice dark malt flavors and aromas if you wait. A month or two minimum though IMO.

 

[SigsNanoBrew]

UPDATE:
The residual sugar test showed little to no levels of fermentable sugars remaining so I am going to go ahead and carbonate with a normal amount of priming sugar.

One part of the recipe I didn't follow exactly was where it says to "ferment down to about 3° Plato (1.012)". Instead, I simply took the fermentation to completion before freezing, adding a diacetyl rest at the end. I believe my final gravity before ice removal around 1.009. So the recipe may explicitly leave some undermentioned sugars in the beer for some reason.

I don't think it will matter much in the end, and I prefer my method because then it takes the guesswork out of priming. Thanks for your input, StoneHands. I still do look forward from hearing from anyone who has made an eisbock.

 

[XPLSV]

How has your bottle conditioning regimen turned out to this point? I have getting ready to brew one of the two recipes from that article...I generally only force carb, but considering the aging associated with this type of beer, am considering bottle conditioning some for long term aging.

 

[SigsNanoBrew]

How has your bottle conditioning regimen turned out to this point? I have getting ready to brew one of the two recipes from that article...I generally only force carb, but considering the aging associated with this type of beer, am considering bottle conditioning some for long term aging.

Hello, I'm glad you are interested in this topic.

I was successful, using normal priming sugar calculations & assuming there are no residual fermentable sugars in the finished beer. The beer came out fine -- you don't have to worry about bottle bombs if you just prime as usual. However, because this beer is such high gravity, because of the combination of high alcohol, cold, and long storage, some fresh priming yeast should be used.

I use Danstar Cask and Bottle Conditioning Yeast CBC-1 in my beers. I find that conditioning is faster and more consistent than relying on the yeast that is present after fermentation. You could use any yeast that is tolerant of high alcohol and flocculates well. The CBC-1 meets these requirements. The re-inoculation rate is about 2g or ½ teaspoon per 5 gallon batch.

I primed the beer at about 2.2 volumes of Co2, based on recommendations for barley wine. I've tried a few, they taste good, very dark and rich, it's almost a dessert beer. There was decent carbonation after 4-6 weeks. It never really develops much of a head though. I'm aging the majority of them. There is a bit of a bite that I hope will mellow out over time.

Good luck.

 

[XPLSV]

Thanks for the info! Will be a few months before I use it, but it will definitely help.