PDA

View Full Version : Sluggish Fermentation - Grand Cru Ale


Mad Zymurgist
02-28-2004, 10:59 AM
Hail all beer zealots,
This is my situation. I'm making my 3rd batch ever, it's a high gravity Hoegaarden Grand Cru mimick, starting at about 1.060. The primary fermentation was aggressive for the first 24 hours and then quickly subsided into a secondary that bubbled at a rate of 10 bubbles per minute. Over the next 2 weeks it slowed to a rate of 6 bubbles per minute, but has held steady. It's been 21 days now and the bubbling continues at 6 bubbles per minute.

I was afraid that a wild gusher strain was at work, so, I decided to check the gravity and attenuation. It started at 1.060. Now, it's at 1.030. The target is 1.010. The bit I tried was quite sweet so I think the fermentation is just sluggish. I gave it a swirl and put it in the warmest room in our house (about 75 C) to see if I could wake up the yeast. It just continued at the same rate. So, I bought another 5-gallon carboy and racked it to a secondary fermentor last night, then pitched a fresh batch of Belgian Wit Ale yeast.

It's been a few hours and I've got a layer of krausen across the top which is a good sign. The rate is about 10 bubbles/minute still though. At least I got the beer off of the trub. I hear the sediment starts to impact once dead yeast are metabolized via glycolisis. There were definitely dead yeast cells floating around. I'm going to sit a few days and see what happens. I can't bottle when it's still bubbling so much. Also, I can't stand how sweet the beer is. The flavor would be awesome if the sweetness would go away.

Here are my questions:
1) The Belgian Wit yeast seemed to poop out early. Does anyone know if it's particularly sensitive to high alcohol content? If I use a more aggressive yeast to finish the ferment, will it ruin the taste? (i.e. - I hear champagne yeast works for high gravity)
2) I used a recipe that called for 7 lbs light extract, plus 2 lbs of honey. Has anyone else noticed that honey takes longer to ferment? I've been reading that mead (using only honey) can take a very long time. I'm wondering if the sugars are different and the yeast strain is having difficulties with it.
3) I had a dilemma when racking the beer last night. I didn't want to oxidize the beer and ruin the flavor, but I wanted my yeast to thrive in a well-aerated environment. So should I aerate when racking to a secondary or not? I know it's too late this time, but it would be nice to know for next time. I just siphoned carefully without splashing and hoped that the wort would aerate enough with the transfer to give the yeast a nice place to live. I couldn't bring myself to shake it up. I hate stale beer even more than sweet beer.
4) What is the minimum bubbling rate before I can bottle?

Thanks in advance.

toneyc
02-28-2004, 05:32 PM
Wow, yes, honey does take longer, but 21 days does seem excessive. It sounds like you've done everything properly. It pretty much seems the consensus around here, never aerate after fermentation starts, even if adding additional yeast. 1.060 to 1.030 is only slightly less than 4% abv, so I would not have expected the belgian wit yeast to give up that early. I made the Gran Cru kit from St. Pat's once, it uses the Belgian Strong Ale yeast. It knocked me on my butt. As for the minimum bubbling rate.... It is when your hydrometer readings do not change for several days. You cannot rely on bubble rate observations. You may not have a good seal and get no bubbles.

:)
Toney.

Fast_Eddy
02-28-2004, 09:01 PM
You never want to aerate your beer past the primary respiration phase of yeast growth.

Tweek
02-29-2004, 11:58 AM
I think it is just that belgian wit strain. It takes its sweet time. If you have activity in the airlock, and Krausen I really wouldnt worry about it. That is why it is good to buy multiple fermenters, so you can fill another one with something quicker :)

Mad Zymurgist
03-01-2004, 05:34 AM
Thanks for the replies.

Here is the update. In the secondary, the beer formed about 2 inches of krausen over a 12-hour period. It continues bubbling once every 10-15 seconds. My hydrometer reading was slightly lower after 2 days. It changed from 1.031 to 1.028. Is that even a change? At that rate I'll be drinking this beer for Christmas. The grand cru is good for racking and aging a bit, but fermenting this long? I don't know about that. It's now been 23 days.

I think I'll just ride it out for now.