Using only base malt?

[akaryrye]

thanks brick, im glad you approve of the recipe.  The westmalle yeast is one beastly animal ... 5 days later and I still have to use a blow off tube, even though the fermentation temps are somewhere between 62* and 65* (they are chillin in my bathroom with the window open)

[Brickhouse]

Yeah, keep an eye on the progress of the yeast.  Use your hydrometer about every other day to monitor the progress.  You probably won't have any problems but if they stall out before reaching your target FG, there are a few things you can do.  The best probably being to just rouse them and be patient.  Keep us up to date.  Those of us who don't have the time to brew right now will live vicariously through your efforts!

[BrewerDano]

Yeah...  No time to brew...  Life is busy- 'specially for those of us that survived the labor purge: we took on our missing cohorts workload...

Bring us samples to meetings.  Our first meeting of the year is next Tuesdays- and I'll bring a couple samples of beer.  Not anything from the big brew I wanted to do; but an IPA and Pale Ale I have on tap at the house...  In the next few months I may bring a sample of my currently fermenting Wee Heavy and Imperial Stout.  You'll just have to come to meetings for those!

[akaryrye]

so its 11 days into the ferment and its just at just 1.020 from an OG 1.070.  It still is kinda chugging along, but the bubbles have slowed down.  Would it be alright to raise the temps from 62* to around 68* to dry this thing out a bit more, or perhaps add a bit of invert sugar as well?  As it sits, it is at around 70% attenuation and fermenting at the bottom of the temperature range for this yeast.  Sources suggest attenuation rates of around 76%, but ive also read of people getting as high as 85% which is more in line with my previous experience with this yeast.

[BrewerDano]

Yes, you can raise the temp- although I suggest doing it slowly.  Up to 68 degrees over the course of 3 days.  Rousing the yeast may also help- but be careful not to stir in too much oxygen (a gentle swirling action of the bucket/carboy/conical is what I'd suggest).  I'd avoid adding the sugar- it may change the flavor you desire slightly by adding adjunct and drying it too much (as well as adding fermentables, and thus creating additional alcohol to effect flavor)

[Brickhouse]

70% is pretty good for this yeast, but you should be able to get down to 75% without any problems (remember this yeast should get between 72 and 78% attenuation).  Note also that your mash schedule should have produced a higher than average fermentable wert.   If nothing else, you'll want to bring the temp up to decrease the diacytle you'll have with a low temperature end ferment.  You will already be dealing with quite a bit of fruity esters with your belgian yeast anyway, but a low temp ferment generates the most diacytle.  Give it a taste now looking for buttered popcorn.  I suspect you'll need to decrease the diacytle some and bringing the temp up will also help the yeast to chew on the remaining sugars. 

I would avoid adding simple sugar at this point.  It's best  to plan for incremental sugar additions as the ferment progressess.  If you do it now not having planned for it, you'll likely end up with some hot cidery alcohol flavors.  Frankly, I think you have some lazy yeast that have just had a party on the easy stuff and are now slowly working through the more complex sugars.

My advice is to be patient and let it go for another two weeks.    If you still have problems after a week or two, you could pitch an active (in the log phase) fully fed and aeriated quanty of alcohol tolerant yeast.

[BrewerDano]

Thomas is our resident Mr Wizard about knowledge...  But I disagree on certain points.  I hope we all make it to tonight's meeting so we can discuss some points in person (mostly about diacetyl, and it's production).

Come to the meeting!  This is a good topic for discussion!!!

[Brickhouse]

Yeah, Dano I was surprised to see the report that low temp ferments increased "D".  But there it was - measured by a CG and reported in Zymurgy.  I had always perceived more D when I fermented too high.  Then I tasted my next batch which I fermented on the low end and yep, there it was too.  I thought it might just be something you only see with Lager yeast, but the article's CG tables indicate that it occurs with ale yeast too.  I'll edit this post tomorrow with the author's name, the article and the Zymurgy date.

When I run across some verified titbit of information like this I put it in my notes, so that I remember it.  I'm often surprised that what I thought I knew from imprical observation is not what the science tell us.  Did you read the last BYO's not so scientific tests with different pitching rates on the same wert.  They came up with surprising results as well.

[Brickhouse]

Warning:  Geek speak below


You know as I was looking at that article again last night (I know I need to give you the citation), I really got to thinking about how wrong it must be.  I've always seen more D production with a higher temp.  I wonder what was going on.  Here's something to chew on:

From Chris White:  "An intermediate compound in valine production is called acetolactate. Not all of the acetolactate produced eventually becomes valine; some will leak out of the cell and into the beer. This acetolactate is then chemically converted to diacetyl in the beer. The chemical reaction is an oxidation, and high fermentation temperatures favor this reaction. The higher the temperature, the more acetolactate is converted into diacetyl."

Ahh  you say?  So, the article's author's test measurements must be wrong.  Right?  No, I just can't believe that either. 

Let's see: I know that a higher temperature also increases the amount of D that the yeast re-absorbs. So maybe what he author measured in the low temp ferments was residual D that did not have a chance to be, or was more slowly, reabsorbed therefore his test showed elevated D.  Perhaps it was his procedure not the measurment that was defective.  If he wanted to compare the D production he should have made his measurement before the yeast went into to the stationary phase for all yeast and for all temperature variables.  If he made his measurements after the statonary phase, and did not perform a D rest, then yes you might expect to see greater D remaining in the beer in the lower temp fermentations.

But, even with more absorbtion on the higher temp ferments would that overcome the greater amount of acetolactate converted into diacetyl?  It's still not clear.

[BrewerDano]

"Perhaps it was his procedure not the measurement that was defective."

That is the same idea I thought.  Possibly, his boil wasn't hard enough to reduce the amount of D (diacetyl, for those lost) pre-ferment.  So, perchance he began with a flawed start- that would end result in flawed information.  I always understood ale yeast to be a low D producer at lower temps; and lager yeast to produce plentiful D: thus the need for a D-rest. 

Any article in BYO and Zymurgy is a good one- but one must remember that they are oft written by homebrewers, like me and you!- that may not have the scientific background to fully understand end cause-result information. 

Brew your own beer, and follow the advice of known and proven sources like Greg Noonan, Terry Foster, & Ray Daniels.  They are beer scientists that brew excellent beers, have studied topics about beer production, and have published books.  I tease Thomas here on the forums for being Mr Wizard- but it's out of admiration and respect (really; jealousy), because he reads and practices the info and techniques I wish I had the time to do.  If you have the time- brew the same beer; your favorite style or clone beer- and do it just a little differently each time.  Different mash temp or time, different fermentation temp or time (if you primary and secondary ferment), different base malt or hops.  Truly experience the world of differences that can make great beer!  Keep brewing!!!

[Brickhouse]

I'm just trying to understand the "magic".  It's one element of the hobby that I truly enjoy.  There is just so much going on when you brew, it's hard not to want to understand what is happening.  I guess that's why we have so much contridictory information out there.   

[akaryrye]

This has been interesting reading everyone's replies!  Just an update:  2.5 weeks now since I pitched the yeast and I raised the temperature to like 68 about 5 days ago.  It is still bubbling slowly and I havn't taken a gravity reading.  After raising the temperature, the krausen reformed and hung out for a day or so!  I will give it another 5 days, measure the final gravity and then cold crash so it will be ready to load into kegs next weekend.

Oh, one more quick question:  Force carb or cask condition?  I like how quickly force carb gets the beer ready, but then again a cask condition gives the beer a little more time to condition at room temp.

[akaryrye]

Rousing the yeast may also help- but be careful not to stir in too much oxygen.

I dont understand this,  the carboy with an airlock is a closed system and any oxygen is flushed out/consumed during fermentation.  It seems to me that the only thing that even vigorous swirling would do is to carbonate the beer slightly.   

[BrewerDano]

Well, some folk rouse the yeast by inserting a sanitized spoon or other device, and then gently stirring...  Doing such "opens" the fermenter to ambient atmosphere, and can introduce oxygen or bacteria.

[akaryrye]

final gravity came down to 1.009    (about 85% attenuation).  The sample tasted ... well im not sure i like it yet, definitely not while it is flat and room temp.  Plus there was some yeast still in suspension affecting the flavor.  It is thin and dry of course with a little bit of alcohol on the nose.  Yeast threw down a nice mellow fruitiness.  I am no expert, but i don't think there is any diacytl in there.  Peter told me that the Perle hops might lend a slightly harsh flavor and I think he is right, another choice for at least the aroma hops would have been better.  If nothing else, it is beer!  Now i will chill it, keg it and set it in the closet for another month or so before cracking one open.

whew, strong stuff ... got a little buzz from the 1/2 pint i drew for sampling ! 

[akaryrye]

Well, its been somewhere between 6 - 7 weeks since brewing and I am drinking a pint right now.  It has turned out alright, thought I must admit I was worried for a while at all the hot alcohol flavors and overly yeasty flavor that it had at first.  I like it ... though I am a bit biased.