[mtnandy]

So I have had a belgian golden strong fermenting away for about 10 days now. Krausen is completely gone and I have had three consecutive readings of 1.025. OG was 1.092. I used a 3.5 liter starter of 1388. I tasted a sample, and it was incredibly sweet, almost like the yeast didn't ferment all of the cane sugar that was added to dry the beer out. I started the fermentation at around 65F, and gradually ramped up to 78F. Any ideas on what is happening? Is it a conversion issue? I tried mashing low, around 147, but I accidentally got too low, and ended up mashing around 143 for 90 min. Would that affect conversion? If I want to dry it out more, what do you think about adding brett? I've never used it before, but I have read that it will eat anything, and I really like the  trappist ales. Any other suggestions?

[morticaixavier]

can you give us more recipe details? 143 is low but I don't think it is too low to cause incomplete conversion, besides you say it tastes sweet so that implies conversion happened just fine.

[davidgzach]

Ya.  If anything, sounds like your conversion was just fine and the yeasties should have plenty fermentable sugars to keep eating if you were in the mid-140's.  Do you use any software to check your conversion %?

Only other thought would be to pitch a couple more packs of 1388.

[rstansbu]

A couple of things come to mind....

For one, you might not have had enough yeast cells.  It could be that your yeast viability was very low.  Do you know how old the smack pack was?  Also, how many smack packs did you use in your 3.5 liter starter?  I typically "underpitch" that yeast on purpose (target ~15-20% below what JZ's yeast calculator spits out), but if you only used one smack pack with low viability in your starter, I could definitely see it stalling out at 1.025.

Another thing could be the temperature.  You ramped the temperature up to 78F, but did you keep it there?  After the initial vigorous fermentation activity is finished (when the most heat is generated), the temperature will drop as the activity slows.  If you don't have some way of heating your fermenter, the yeast can become inactive and crash once the temperature falls.  I've seen this for myself, and it's a phenomenom that Stan Hieronymus describes in his book "Brew Like a Monk."  And ramping the temperature back up doesn't jump start the yeast again either...they are just sensitive.  I had this happen to me on a Belgian Dark Strong a few years back, and I couldn't do anything to get fermentation rolling again, including pitching new yeast at high krausen.  I eventually pitched a few strains of Brett in and set it aside for a few years.  The end result was really nice.

[denny]

Ya.  If anything, sounds like your conversion was just fine and the yeasties should have plenty fermentable sugars to keep eating if you were in the mid-140's.  Do you use any software to check your conversion %?

Only other thought would be to pitch a couple more packs of 1388.

Here's a chart from How to Brew.  Looks like beta amylase is active all the way down to 130 so you were in conversion range.  How long did you mash?  Generally, the lower the temp, the more time you need.

[snowtiger87]

Have you tried rousing the yeast? I would do that every day to see if you can get them kicked back up into the beer. I would not waste money on more 1388. After a week of rousing with no favorable results I would just add a couple packs of Nottingham dry yeast or SA-05. By now you have gotten most of the character from the 1388 yeast anyway.

Brett may not do anything at this alcohol level.

[tschmidlin]

It might just be done.  1.092 to 1.025 is pretty good attenuation, especially when you mashed at 143F.  Even 90 minutes might not have been long enough to convert everything.  Warm and flat, the beer could be coming across as sweeter than expected, and sweeter than it will taste when it is colder and highly carbed like Belgian golden strongs usually are.

[bluesman]

92 TO 25 is not bad at all. The yeast probably chewed up everything that they liked and flocculated out. Mashing temp, oxygen level, amount of viable cells and fermentation temp all play a significant role in the outcome of the finished beer.

Take a small sample (1 pint) of the beer and put it into a small jar then add some US05 dry yeast (1gm). If you get some further attenuation you know that there is more fermentable sugar.

[mtnandy]

can you give us more recipe details? 143 is low but I don't think it is too low to cause incomplete conversion, besides you say it tastes sweet so that implies conversion happened just fine.

13.5 lbs pilsner malt
3 lbs cane sugar

mash pH was held at 5.3 during the 90 min mash.

Beersmith was expecting 1.023, so I'm pretty close, I was just hoping to make a super-dry belgian and was wondering if it was even possible to dry it out more. I figured that since I mashed so low, I would be able to get it down lower than Beersmith's expected FG.

[kylekohlmorgen]

1.092 to 1.025 = 78% App. Attenuation

Wyeast gives the attenuation range of 1388 as 73-78%

1.016 will get you to the upper end of the FG (and ABV) of the BJCP guideline, which is about 83% attenuation. You're best bet is:

1. Rouse the yeast. Check for activity visually via bubbles in the airlock or yeast re-suspension. Try not to take too many samples - you may expose your beer to too much air.

2. If the beer isnt >70F now, raise the temperature to encourage yeast activity. 70-72F oughta do it.

3. If you have to repitch, use the Wyeast Imp. Blend. It will be more tolerant of the alcohol levels. Champaign/wine yeast, in a Begian Strong, with high temps, yields a big risk of cidery flavors or over-attenuation (or both).

.

[kylekohlmorgen]

Sorry, forgot one thing:

If you do get the FG down, you're looking at ~10% ABV. The flavors will be harsh and solventy at first. Put it in a keg and give it some time. At least 3 months, but 6-8 will be better!

[jjflash]

I brew almost exclusively Belgian Style beer including Golden Strong.
I am meticulous in all details, yeast counts under the microscope, oxygen saturation meter, etc, etc.
Seems like I can do ten batches in a row and all is perfect, but then one will come up long on FG.
Most of the time I can never pin point exactly where something didn't go just perfect.
These really big beers are very unforgiving of mistakes.

Everyone has given you good advice.
To salvage your beer you need to repitch a new starter.
Don't bother trying to rouse the yeast - waste of time.
All your beer flavor has alreeady developed from your initial fermentation.
I usually make a one liter starter with WLP 099, the high gravity Thomas Hardy yeast.
Stir plate for 24 hours and pitch at high krausen.
Works every time for me.

[ukolowiczd]

I brew almost exclusively Belgian Style beer including Golden Strong.
I am meticulous in all details, yeast counts under the microscope,

How does one do that - count yeast under the microscope - I'd love to try it?

Also I agree with pretty much everything here. Temperature is king with Belgian beers. I always keep my primary in a heated 75F room for at least 2 weeks with big Belgian beers. Although like someone else said, 1.025 is a pretty good FG for starting in the 90's. Like the many Belgians that I make, 2-6 months in a bottle/keg mellows them out beautifully. Perhaps the sweetness will decrease.

[jjflash]

How does one do that - count yeast under the microscope - I'd love to try it?

http://www.whitelabs.com/beer/microscope.html

[snowtiger87]

That is some great information. It makes my head hurt reading it but great anyway.

You are correct about rousing the yeast now. It probably won't do any good if it has gone dormant. I normally start rousing when the fermentation shows signs of slowing down - not when it appears totally finished.