Stuck fermentation with Windsor yeast

[rpt]

I'm brewing an oatmeal stout with Windsor yeast. It started at 1041 and after 3 days at 20C was down to 1019. After 3 more days it was still at 1019 so I increased the temperature to 21C and roused the yeast. I've increased the temperature by 1C every day so that today, 2 days later, it is at 23C. It is still at 1019.

I know that Windsor is a poor attenuator but this is an apparent attenuation of only 53%. I was expecting 60% at the very least, which would have been 1016.

I mashed at 65C and I rehydrated the Windsor before pitching.

So, what should I do next?

• 1. Be patient. It will get lower given time.
  2. Keep raising the temperature.
  3. Rouse the yeast again.
  4. Pitch some more yeast. I have some Gervin ale yeast. Should this be made into a starter and pitched at high krausen?
  5. Transfer to a secondary. This will be a better way of rousing the yeast.
  6. Bottle it. With such a high FG I'd be worried about bottle bombs but if it's actually finished then this shouldn't be an issue. Before bottling I would lower the temperature to help the yeast drop out.

I've just had a taste from the hydrometer sample and it does taste pretty good. It probably is a little sweeter than my first attempt at an oatmeal stout, but this is a beer where that doesn't matter - it nicely compliments the roast barley.

It contains roast barley, flaked barley and oats, and I did read that they may mash to sugars that Windsor struggles with. I did an oatmeal stout before that used Nottingham (I pitched it straight onto the yeast cake from a previous brew) and that went to 74% apparent attenuation (although the recipe was slightly different).

 

[NickW]

I did this recipe too... was this alemans recipe?

I Got it down to 1.012 at a fermentation temperature of 18c.

Was the yeast in date when it was pitched?

 

[rpt]

No, not Aleman's recipe, but similar. The yeast was in date and kept in the fridge since it came from the Malt Miller in April.

 

[NickW]

You're probably more knowledgeable than me, but what about pitching more Windsor? The gervin ale yeast might not produce the profile you want.. worth a go.

 

[rpt]

I'm pretty sure any Windsor flavours will have happened by now so the new yeast would just be to finish off any residual sugars. Plus I don't have any Windsor to hand.

 

[NickW]

I quite like the lowish attenuation of windsor as it leaves a little more body in the beer. Gervin ale yeast would probably munch on more of the sugar.. but if I were in your shoes issue probably do the same thing.

 

[rpt]

So you're suggesting I add the Gervin yeast?

I'm actually tempted to leave it for a few days to see if it ferments a bit more. If it doesn't, I'll lower the temperature to let it clear a bit and then bottle it. I'm not too bothered by the sweetness as it isn't very obvious and suits the style, but my main concern is bottle bombs. I guess I'll just use less priming sugar - stout doesn't need to be very fizzy. It will be a pretty low ABV brew but if the taste is good then who cares.

I was hoping someone else might have an opinion - perhaps few people have used Windsor. It doesn't seem to have a very good reputation.

 

[NickW]

If it was 1.018+ I'd be tempted to add another more attenuating yeast as I'd fear it had stuck, as you say... bottle bombs. But, saying that, if you mashed at 68c+ then perhaps it's as far as it'll go. I mashed at 66c for 90mins with mine - what temp did you mash at?

 

[Aleman]

Insufficient Aeration!

 

[rpt]

Insufficient Aeration!

I wondered that but Danstar say you don't need to.

 

[NickW]

Insufficient Aeration!

I wondered that but Danstar say you don't need to.

I believe dried yeasts have sufficient nutrition so they don't need to be aerated.. but I always aerate to the point of dropping the wort into the FV from the tap on the boiler (when its cooled of course).