Can't restart a stuck fementation

[Glynn]

I have a batch of dipa that has stopped at 1.040. The yeast is washed pacman that i made a two step starter with. I pitched it at 60 and fermented it at 60. it took off fast and went solid for about a week then died. I have tried warming it back up to 72 with very little response. Today i stirred it up with a racking cane and am raising the temp back up. If it doesn't take off im considering racking it off and washing the yeast and re pitching with 1056 or 1272. Is it worth washing the pacman? i really didn't want to loose this strain as it was the first time i got to use it and really wanted keep it around for a while

 

[IL1kebeer]

You don't have to go through all of that. Just pitch a 1-2 pint starter at 6-8 hours. The yeast will be awake and seriously ready to go. It'll finish that up for you.

 

[Glynn]

Well I re pitched with a starter of 1056 after racking it off the old yeast about 48 hrs ago. it's started to ferment again, although very slowly. only got about a 1/4" head on it. I hope it's enough

 

[Brewskii]

You sure about that 1.040? Pacman is aggressive as I recall and if you had good activity for 6 days... I'm thinking it's gotta be lower than that. Even a strong IIPA I wouldn't expect to actively ferment much longer than that.

 

[FarmerTed]

Are you using a new refractometer to measure the F.G., and did you forget to do the conversions to calculate the real F.G.? It sounds to me like you should be done, too.

 

[Glynn]

I use a hydrometer and checked the batch twice about 2 days apart. I thought it was done at first also so i started to cold crash it. Two days into the crash i checked the fg and realized it was not. so i warmed it up and roused it but nothing happened. the rest you read. the only thing i can think is i didnt get as much yeast from the 2 step starter as i thought

 

[Brewskii]

I use a hydrometer and checked the batch twice about 2 days apart. I thought it was done at first also so i started to cold crash it. Two days into the crash i checked the fg and realized it was not. so i warmed it up and roused it but nothing happened. the rest you read. the only thing i can think is i didnt get as much yeast from the 2 step starter as i thought

Yes, I was thinking YCC could really only be the other explanation if it really is that low. Beyond catastrophic mashing temps of course.

If so, you should be fine now that you added some 1056. Keep it in the upper 60's and ride it out. Did to take a gravity today? Is it still working?

 

[bearfootbrewer]

Sounds like to me you might have had a low mash temp. Not letting the enzymes completely convert the starches to fermentable sugars leaving unfermentables behind raising your FG. I did not see but what was your OG? If all else fails add some Dextrose (corn sugar) to jump start is again.

 

[Glynn]

Sounds like to me you might have had a low mash temp. Not letting the enzymes completely convert the starches to fermentable sugars leaving unfermentables behind raising your FG. I did not see but what was your OG? If all else fails add some Dextrose (corn sugar) to jump start is again.

my og was 1.075 and my mash temp was 154 and if im not mistaken its the opisit of what you are saying lower mash temps produce more fermentable sugars and less body. high mash temp do the opposite. Plus the recipe already had 1.5 lb of dextrose added to the pre boil. The only plausible reason was lack of yeast from the starter and way to low fementer temps

 

[bearfootbrewer]

my og was 1.075 and my mash temp was 154 and if im not mistaken its the opisit of what you are saying lower mash temps produce more fermentable sugars and less body. high mash temp do the opposite. Plus the recipe already had 1.5 lb of dextrose added to the pre boil. The only plausible reason was lack of yeast from the starter and way to low fementer temps

yes I agree with you probably is a low yeast cell count and low fermenter temp.

 

[BigFloyd]

Yes 154 is right in that sweet spot and also alittle on the low side for the fermentable sugars, any lower you get unconverted starches that leave the wort sweet and unfermentable.

Any lower than 154*F mash leaves unconverted starches? Where in the world did you hear that?

Oh, I see that you've now edited to delete that.

 

[WissaBrewGuy]

Sounds like to me you might have had a low mash temp. Not letting the enzymes completely convert the starches to fermentable sugars leaving unfermentables behind raising your FG.

It is the opposite of this. High temp=unfermentable sugar/sweet beer. 154 is just right.

 

[Brewskii]

Not to pile on but, if the guy has 1k posts on HBT you gotta figure he's got the usual suspects covered.

 

[Glynn]

Not to pile on but, if the guy has 1k posts on HBT you gotta figure he's got the usual suspects covered.

One would think

 

[bearfootbrewer]

Any lower than 154*F mash leaves unconverted starches? Where in the world did you hear that?

Oh, I see that you've now edited to delete that.

149 is the low for is Alpha-amylase , the enzyme that breaks down the starches to fermentable sugars. any less you get a wort rich in starch chains AKA dextrin sugar. Dextrins are non fermentable.

Now there is a enzyme that work at a lower temp (Bete- amylas), but with out giving Alpha-amylase the time at the temp they need you will not get full conversion, leaving that sweet dextrin.

The same thing will happen at high temps as well. Its the same because the enzymes are not in that sweet spot of around 156 -158.



Anyway I hope you got it to ferment down to the FG you wanted.

 

[beersk]

Add some amylase enzyme if none of the usual tricks solve it issue.

 

[bearfootbrewer]

The edit was to get me exact temps. If you go to post 15 you can read all of it.