My stouts always get stuck during fermenting.

[Chico1980]

Does anyone else have a issue with stouts getting stuck during fermentation or slowing to a crawl towards the end. No matter what I brew kits or all grain my stouts and porters seem to stop at about 1.020. They all seem to need extra heat 20oc+ and sometimes a rouse. They mostly finish a few points down in the end but it’s the only beer style I ever get bottle bombs from.
I ferment in a cellar with a steady temperature of 18oc, I’m happy to give the beer time, and have minimal issues with other styles.
Strange, any thoughts.

 

[The Baron]

What is the yeast you are using?
What is the OG of the wort?

 

[Chico1980]

With a kit, whatever comes with it.
With all grain usually something from CML I like to mix it up and try different years with similar grain bills.
Current oatmeal stout 23l 1.050 SG had two pouches of Wilko Kit yeast pitched at 18oc and that’s stuck.
Only have a issue with stouts. Both kits and all grain so it’s not mash temp. I brew 2-3 times a month.
Didn’t know if stouts getting stuck was a thing or not. Or just a massive coincidence.

 

[An Ankoù]

Put a teaspoonful of yeast nutrient in the brew at pitching time.

 

[Chico1980]

Put a teaspoonful of yeast nutrient in the brew at pitching time.

Any suggestions of what to use. Always just relied on the yeast and a good whisk to get some air in.

 

[chillipickle]

https://www.themaltmiller.co.uk/product/wyeast-beer-nutrient-blend/only need 1/2 t spoon, it works very well.

 

[moto748]

Maybe just a bit warmer? I've never had this issue with stouts, but all my beers are brewed at room temperature. Which may not be ideal for some styles, but as I say, I've never suffered from stouts 'stopping'.

 

[Sandimas]

I seem to get this too, not every time but often with dark beers. Back in the summer one stuck at 1025 and wouldn't budge, so I still bottled it. I thin the yeast re-started as it got a bit foamy towards the end of the batch but no bottle bombs.

I tried an experiment before Xmas and mashed a bit lower (63C), this time it went right down but took a long time to get there with MJ Empire Ale Yeast, 25 days in total. What temperature do you mash at?

 

[MartinF]

I also have similar problems, not just with stouts but - to some extent - all dark beers. Porters, Hefedunkles, dark milds, always all grain. Tried different yeasts - liquid & dried, aeration/non-aeration, different mash temps, rousing, extra long fermentations, raising fermentation temp.

My current brew, a dark mild, should have finished at 1008. It stuck at 1016. Not a huge discrepancy, but it means an unacceptable 2.9% beer rather than the desired 3.7% (I did shove in some sugar and another pack of a different yeast to get it to 3.7% in the end, though it still only went down to 1015).

I'm at a loss to explain this phenomenon.

 

[ScrumpyRam]

Hi. I've just brewed my first stout. Muntons Flagship Milk Stout and had the same problem. It was in the FV 28 days! OG 1060, final reading 1024.
19l went into a corny and the rest bottled with half TSP of dextrose to prime. The bottles are stood in an empty fern bin with the lid on in case they blow

 

[MartinF]

With a milk stout, there's usually lactose in the recipe. Lactose is a sweetener that doesn't ferment (with brewing yeasts), so that will probably be a contributing factor in this case.

 

[ScrumpyRam]

With a milk stout, there's usually lactose in the recipe. Lactose is a sweetener that doesn't ferment (with brewing yeasts), so that will probably be a contributing factor in this case.

That makes a lot of sense now MartinF. Yeah there must have been a good Kg bag of it that was added at the start of fermentation.

 

[MrRook]

What's your actual recipe?

 

[UKSkydiver]

There is discussion on something similar and theories from @matt76 in this thread here:

PPG and Diastatic power | The Homebrew Forum - Homebrewing Forums

 

[DavidDetroit]

stouts and porters seem to stop at about 1.020.

I make ones with an OG of around 1.110 and getting to 1.030 FG or a little lower is a good number. I just chalked it up to ingredients and some of the stuff isn't fermentable (I don't add lactose). The beer gets there in three weeks. I used to be concerned about it but after some info from others and experience, I'm not.
As mentioned, I always use yeast nutrients and I make sure the yeast is capable of fermenting to X amount.

 

[MartinF]

As mentioned, I always use yeast nutrients and I make sure the yeast is capable of fermenting to X amount.

What yeast(s) are you happy with that'll ferment out dark beers?

 

[DavidDetroit]

What yeast(s) are you happy with that'll ferment out dark beers?

US-05 works well. I use two packs always but that rule kind of developed because of the higher ABVs I make.

 

[foxy]

You need to add more information to get help. Recipe, mash temps, how long was the mash, otherwise its anyones guess.also what proportion of base malt to the flaked oats? Was the oats pre gelatinised?

 

[phildo79]

I have encountered a similar problem but I think only with imp stouts. Not sure I have ever hit the target gravity and quite a few have appeared stuck. My last one was well off target FG. I raised the temp, roused it and the blow off tube started showing activity. But despite days of activity, the gravity never lowered. Someone suggested that the activity could have been co2 dissolving in solution due to the raised temp. I don't think I have ever got a stuck ferment going again, despite trying numerous methods.

 

[MartinF]

US-05 works well. I use two packs always but that rule kind of developed because of the higher ABVs I make.

Interesting. I've only used US-05 with hoppy pale ales. I'll give it a try with my next dark beer. Thx.