Another stuck fermentation thread

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cyderspace

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Hi all,

Sorry another stuck fermentation thread.

Did a grain brew a week ago but mashed a bit high at 70-72 (trying to get a full body beer but overdid it.)

SG was 1043 when I pitched.

The yeast head fell in after 2 days so I took a gravity reading = 1027. That's 2% abv.

But a week on its stuck at 1027.

I had used an old wherry yeast, cos I like that style. But I know wherry yeasts sometimes stick.

I know high mash temperature sometimes strip out the fermentable sugars, so that could be a factor too.

So. Today I have roused the yeast, increased the temperature setting from 19 to 21, and I've added a safale 05 yeast.

OK here's my question to you folks.....

I will wait 48hrs but if that doesn't work I am tempted to add 500g of spraymalt in case lack of fermentables is the problem. Is that wise, and if so, do I just sprinkle it in or melt in water then add? Thanks all.
 
f79.gif

What has happened here is that you have denatured your Beta amylase enzyme in the mash, leaving only alpha amylase to break down the starch in your grain. Alpha amylase breaks chains into sugars at random points in the starch chain, where beta amylase acts on last 2 and 3 glucose in the starch chain, making simpler sugars for yeast to consume. As there was no Beta amylase making simple sugars the yeast has done as much as it can to consume the more complex sugars (dextrines) left by the alpha amylase. Adding more fermentables at this point will not help, your yeast will consume them and leave the sugars they can't consume as they are.

brewing-amylase.png


Rousing the yeast and raising the temperature may help, and the US05 might be more able to ferment some of these complex sugars and reduce your FG. So all is good so far.

Another option is to add some dry hops. This may sound odd, but hops contain Diastase. Diastase are a group of enzymes that will break down the complex sugars into glucose (alpha and beta amylase are part of this group).

You don't really need this next link, although it is a paper from 1941 that explains that Diastase in hops has been known since the 19th century. Here.
 
f79.gif

What has happened here is that you have denatured your Beta amylase enzyme in the mash, leaving only alpha amylase to break down the starch in your grain. Alpha amylase breaks chains into sugars at random points in the starch chain, where beta amylase acts on last 2 and 3 glucose in the starch chain, making simpler sugars for yeast to consume. As there was no Beta amylase making simple sugars the yeast has done as much as it can to consume the more complex sugars (dextrines) left by the alpha amylase. Adding more fermentables at this point will not help, your yeast will consume them and leave the sugars they can't consume as they are.

brewing-amylase.png


Rousing the yeast and raising the temperature may help, and the US05 might be more able to ferment some of these complex sugars and reduce your FG. So all is good so far.

Another option is to add some dry hops. This may sound odd, but hops contain Diastase. Diastase are a group of enzymes that will break down the complex sugars into glucose (alpha and beta amylase are part of this group).

You don't really need this next link, although it is a paper from 1941 that explains that Diastase in hops has been known since the 19th century. Here.

Thanks very much for all the info. If my beer is at 2.5%,will the added fermentables raise this?
 
Thanks very much for all the info. If my beer is at 2.5%,will the added fermentables raise this?
It will, however it will be really sweet from the unfermented sugar already in it. Adding sugar to raise the ABV would be better as it would not add any further sweetness. Ideally you want to get it fermenting again before adding anything more.

What style of beer is it? What IBUs?



"Inspiration is the impact of a fact on a well-prepared mind" Louis Pasteur
 
Sadfield can I ask you if you mash at 65c, the finish off with a 75c mash out, how come it does not effect the fermentability of your wort?
 
Sadfield can I ask you if you mash at 65c, the finish off with a 75c mash out, how come it does not effect the fermentability of your wort?
Because wort is fermentable before mash out. Mash out denatures enzymes and stops the wort being even more fermentable.

"Inspiration is the impact of a fact on a well-prepared mind" Louis Pasteur
 
They sell enzyme additions. I’ve never added it to the FV so I don’t know what will happen. But finally I got a forum buddy that is as geeky as I am on amylase!
To me, it looks like a bunch of un fermentables but also could be a lack of oxygen. You really got to shake it up for a few minutes to get enough oxygen in the wort so the yeast will start it’s growth. Boil a long spoon for a few minutes then gently take of the lid. This is so anything that is setting up shop on your lid doesn’t get kicked up in the air and settle down into your wort. Wild yeasts can eat un fermentable sugars WAY better than brewers yeast. So you don’t wan those dudes in there.
Now stir wildly for a minute or two. Hopefully the addition of oxygen will set the yeast back on track.
But I think Sadfield said s-05 yeast is a better yeast and can attack more complex sugars.
 
If it doesn't drop enough you would be better off adding sugar to up the abv, as this will help dry it out. If you add spray malt then you will add both fermentable and non-fermentable sugars and you already have too many non-fermentables.

I remember reading about a brewery that did what you did and ended up bottling it sweet. The thing is, the yeast was still working on the complex sugars but only very slowly. Over time the pressure built up and they were over carbonated. If I were you I'd hold back a bit on the priming sugar.
 
Sadfield can I ask you if you mash at 65c, the finish off with a 75c mash out, how come it does not effect the fermentability of your wort?

It’s the length of time that is important. Step mashing can really control the enzymes and I would recommend it to brewers who want to up their game on brewing. Starting out at 62 for 15 to 20 minutes then up to 65 for another 20 minutes then up to 68 for the remainder of the mash the ramp it up to 75. From 68 to 75 takes time so your adding the full body to it. But you still have to be critical on your yeast.
 
A boy is given the keys to a sweet shop and told to eat everything he wants.The first thing he does, because he is shocked, is take a sharp intake of breathe. He then eats as many sweets as possible, as quickly as he can. until he is sick. He then falls asleep. When he wakes up he starts eating more sweets, until he is sick again. He again falls asleep. He will carry this on until all the sweets have gone and the shop is empty.
Does this sound familiar?
 
A boy is given the keys to a sweet shop and told to eat everything he wants.The first thing he does, because he is shocked, is take a sharp intake of breathe. He then eats as many sweets as possible, as quickly as he can. until he is sick. He then falls asleep. When he wakes up he starts eating more sweets, until he is sick again. He again falls asleep. He will carry this on until all the sweets have gone and the shop is empty.
Does this sound familiar?
No.

In this sweetshop he's eaten all the Jelly Tots and found the rest of the sweets are too big and hard for this child's mouth.

"Inspiration is the impact of a fact on a well-prepared mind" Louis Pasteur
 
No.

In this sweetshop he's eaten all the Jelly Tots and found the rest of the sweets are too big and hard for this child's mouth.

But when he finds that he's lost the key and can't get out, he has to find something, anything, to break up those big,hard sweets lest he starve to death.
 
Like what Gunge?

Generally, when brewers experience diminished attenuation, there are two likely causes: low wort fermentability or poor yeast performance. Low fermentability can be a result of the ingredients or, for all-grain brewers, hot side processes. It could be a malt extract with a high percentage of unfermentable dextrins, or too high of a mashing temperature. Poor yeast performance is generally a result of poor yeast preparation, but it can also be due to the wort environment.

https://byo.com/body/item/1895-attenuation-advanced-brewing

"Inspiration is the impact of a fact on a well-prepared mind" Louis Pasteur
 
Wherry yeast?
Really?
You must be kidding me.

Wherry yeast is actually not a bad yeast, there just isn't enough of it. I didn't see a brew volume from the OP - if it was 12L or so, a packet of Wherry yeast will have been fine; if it was 23L then yep that's why you have a stuck brew. I always use my leftover Wherry yeasts in small-volume brews.
 
It will, however it will be really sweet from the unfermented sugar already in it. Adding sugar to raise the ABV would be better as it would not add any further sweetness. Ideally you want to get it fermenting again before adding anything more.

What style of beer is it? What IBUs?



"Inspiration is the impact of a fact on a well-prepared mind" Louis Pasteur

It's a copper colour bitter
 
I intentionally mashed my last brew high at 70c. I wanted to see if it would do anything for body and raising the FG. I'll post the results when available.

No readings taken but the airlock activity is a lot less than that of lower mash temperature brews, peaking on day 2 and falling right off after that.
 
I intentionally mashed my last brew high at 70c. I wanted to see if it would do anything for body and raising the FG. I'll post the results when available.

No readings taken but the airlock activity is a lot less than that of lower mash temperature brews, peaking on day 2 and falling right off after that.

Ditto, I've just done a beer where I intentionally mashed at 72c, was aiming for 0.5% abv but came out at 0.6%. Came out well, but obviously a low alcohol beer and slightly thinner than a standard brew, but highlights how extreme a mash temperature it was. Look forward to seeing your results.
 
Ditto, I've just done a beer where I intentionally mashed at 72c, was aiming for 0.5% abv but came out at 0.6%. Came out well, but obviously a low alcohol beer and slightly thinner than a standard brew, but highlights how extreme a mash temperature it was. Look forward to seeing your results.

S**T! I'm not trying to go that low! Hoping to finish at 1.010- 1.020 max. It's an experiment though
 
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