Stuck fermentation?

Hello everyone,

I started my first AG brew a few weeks ago. It is a rye beer. The original gravity was 1.044. I am using the white-labs wpl029 and i am now stuck at about 1.022. I have been having a difficult time keeping the temp at 70 b/c my house is really drafty. I have tasted the brew and it tastes like there is no residual sugar. Is the fermentation stuck? Have I overlooked something? Is it possible that the gravity is being influenced by another factor?

Please enlighten me with your grand collective HBT knowledge.

Thanks in advance

1.022 is a bit high- you should get 1.010 or so with that yeast.

What was your recipe and your mash schedule like?

Recipe and mash:

5.5 lbs German pils
3 lb caramalt
1 lb rye malt


Single infusion, batch sparge

mash in @ 170.5
sparge at 168
mash output total was: 7.26 gal

I did boil for 120 minutes b/c I still had too much water left in the wort after 60. I also did an iodine test just now and i'm not showing any residual sugar.

Let me know if you need more info.

tetrylone said:

Recipe and mash:

5.5 lbs German pils
3 lb caramalt
1 lb rye malt


Single infusion, batch sparge

mash in @ 170.5
sparge at 168
mash output total was: 7.26 gal

I did boil for 120 minutes b/c I still had too much water left in the wort after 60. I also did an iodine test just now and i'm not showing any residual sugar.

Let me know if you need more info.

Click to expand...

What was the mash temperature?

Actual mash temp was 158 for 1 hour.

Not sure if this helps with the diagnosis but 36 or so hours after pitching yeast I could see the kreusen begin to rise, then about 1 hour later it had fallen. it never really seemed to get going.

anyone else have any ideas?

Kinda hung on what to do,.. should I try to pitch another yeast? Anyone have any ideas on how to:

1) Make sure there are no more sugars left
2) Revive a fermentation when it arrests

or have any other input?

Iodine does not test for residual sugar. It tests for residual starch to make sure that it was all converted to sugar.

Your fermentation is done. 1.022 would be high for that yeast but your 3 lbs caramalt leaves a lot of unfermentable sugar. THEN your mash temp leaves a lot more. 1.022 is exactly where I would expect those recipe parameters to end up.

This beer will end up sweet but it should still be good, so it is not really broken. However, if you really feel the need to try something you can pitch a higher attentuating yeast. Champagne for example. That should get a few more points off.

Your goal is not to make sure there are no residual sugars. If that were the case then your beer would be very very dry. The goal is to balance the sugars with the hops and other elements in the beer.

I read somewhere that one could add amylase to a fermentation and that it would help to chop down the unfermentables. Does anyone know of this?

BTW Thanks dontman. Do you know what (name of) sugars in caramalt that are usually unfermentable? Also should I have used a multi-step mash instead of the single infusion?

tetrylone said:

I read somewhere that one could add amylase to a fermentation and that it would help to chop down the unfermentables. Does anyone know of this?

BTW Thanks dontman. Do you know what (name of) sugars in caramalt that are usually unfermentable? Also should I have used a multi-step mash instead of the single infusion?

Click to expand...

Yeah, you could add beano but from what I've read, you will have a dry beer.

The sugar in caramalt is maltose. That grain produces a sugar when mashed that is too complex for yeast to consume.

A single step mash is fine for that grain bill. Next time, keep it closer to 150.

The higher mash temp, (158) will give you a starch to sugar conversion but it will also give you some complex sugars from the pale malt that are unfermentable.

Here is a good place to start reading up on mashing.

Cookiebaggs said:

Yeah, you could add beano but from what I've read, you will have a dry beer.

The sugar in caramalt is maltose. That grain produces a sugar when mashed that is too complex to be broken down into an easily fermentalbe sugar.

A single step mash is fine for that grain bill. Next time, keep it closer to 150.

A higher mash temp, (158) will give you a starch to sugar conversion but it will give you complex sugars that are unfermentable.

Here is a good place to start reading up on mashing.

Click to expand...

Perfectly answered.

To be honest, if this is one of your first brews, or first AG brews, I think you should let it be. Maybe give it another week to see if it drops a little on its own, maybe give the fermenter a quick swirl to rouse the yeast but if nothing happens don't worry, bottle it up, wait a few weeks and enjoy.

I agree with last post. Rouse your yeast, warm to at least 72 degrees and give it a week. If still at 1.022 then don't mess with it.

I had a similar problem with an all grain batch. I mashed too high and it was stuck at 1.030. I ended up adding some corn sugar and malt to the primary to bump the alcohol a little. It was only about 2% before I added it. It tastes pretty good now and I am going to bottle it this weekend. I also pitched some Nottingham to help. Don't use Beano because it won't stop until it 1.000 and you could end up with a really dry beer or bottle bombs if you bottle.

Thanks everyone for your help!