M15 Empire Ale Yeast

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Just wondering what people's experiences of MJ M15 Empire Ale yeast are?

Used it a few times in the past and, being a medium-attenuating yeast, it always finishes a bit high. But just bottled a Porter and FG was 1025 (OG1051). So my expected 5% beer has turned out a measly 3.4% with a yeast attenuation figure of 51%: that's the lowest-ever by a long way, in 197 brews.

So I'm wondering what went wrong? The brew was under temp control, and in the FV 20 days, and definately seems finished. Grain bill was loosely based on Fullers London Porter, so 14% Brown Malt in addition to 10% Crystal: could this be the culprit? I have brewed with this grain bill before using different yeasts and got FGs of 1016 and 1012, so I don't think this is the problem, but it's the only brew I use Brown Malt in and am unfamiliar with it.

The only other thing I can think of is that the yeast is too old. Have thrown the packet now, it was stored in the fridge but I think it was one of the older ones in my stash.
 
It’s a low-medium attenuator according to the specs. Even then, you’ve only got 50% attenuation as opposed to the 70% in the specs so I’m not sure what your issue is.
 
That FG is too high. What was your mash temperature? The brown malt shouldn't make that much of a difference as it's not a crystal or caramel malt and it's starched will have been converted in the mash. you could try adding a more attenuative yeast to finish it off, M42 or M36 or a sachet of Wilco Gervin for a quid. If that doesn't work try adding a few CCs of amyloglucosidase or a similar enzyme.
 
My experiences with porters and stouts (dark grains) is that they attenuate always less, and this is more pronounced with low attenuating yeasts.

In the dark pasts of porter and stout, a whole lot of the fermentation was done by brettanomyces, which brings the FG further down after the main fermentation.

Use a more attenuating yeast, and if you use many dark (roasted) grains, double the amount of yeast. The roasted malts put more stress on the yeast.

You could also try to specialise in Scottish stouts.
 
I think it could have been out-of-date yeast.

I tracked down the order of the M15 to August 2019. I use a different supplier now (Malt Miller), just had an order from them and their yeasts typically have a 2-year use-by date, late 2022. However, I've found another yeast from the old supplier, a later order Jan20, and that yeast is already out-of-date: it only had a 9-months left. Lesson learned, I guess there's a reason why some suppliers are cheaper than others.

I do brew Porters regularly so am familiar with higher FGs, just not 1025. I've bottled it now and will check them regularly, any sign of bottle bombs and the caps will all come off.
 
I think it could have been out-of-date yeast.

I tracked down the order of the M15 to August 2019. I use a different supplier now (Malt Miller), just had an order from them and their yeasts typically have a 2-year use-by date, late 2022. However, I've found another yeast from the old supplier, a later order Jan20, and that yeast is already out-of-date: it only had a 9-months left. Lesson learned, I guess there's a reason why some suppliers are cheaper than others.

I do brew Porters regularly so am familiar with higher FGs, just not 1025. I've bottled it now and will check them regularly, any sign of bottle bombs and the caps will all come off.
Don't be too sure. Packet yeasts can last for years and years. I reckon the date stamp is for stock rotation. I've used dried yeast nearly 10 years out of date and it has worked fine. I think yeasts either work or they don't, but they certainly don't change their fermentation characteristics while in the dry state. Have you tried rousing the yeast, by the way?
 
Yes, roused it a couple of days ago, there was briefly some activity then it stopped again. I did wonder if it was my hydrometer but I have two and both read the same.

The beer actually tastes really nice.
 
Just wondering what people's experiences of MJ M15 Empire Ale yeast are?

Used it a few times in the past and, being a medium-attenuating yeast, it always finishes a bit high. But just bottled a Porter and FG was 1025 (OG1051). So my expected 5% beer has turned out a measly 3.4% with a yeast attenuation figure of 51%: that's the lowest-ever by a long way, in 197 brews.

So I'm wondering what went wrong? The brew was under temp control, and in the FV 20 days, and definately seems finished. Grain bill was loosely based on Fullers London Porter, so 14% Brown Malt in addition to 10% Crystal: could this be the culprit? I have brewed with this grain bill before using different yeasts and got FGs of 1016 and 1012, so I don't think this is the problem, but it's the only brew I use Brown Malt in and am unfamiliar with it.

The only other thing I can think of is that the yeast is too old. Have thrown the packet now, it was stored in the fridge but I think it was one of the older ones in my stash.

I always find this yeast finishes high but that sounds even higher than I would expect so either through the mash you’ve produced a lot more non-fermentable sugars (eg mashed high) or fermentation is not yet complete. It might be a good idea to make sure at least one bottle is a plastic one so you can keep an eye on the carbonation levels and avoid exploding bottles.
 
Not too full-bodied and sweet on the finish?

No, and that kinda surprised me, I was expecting it to be too sweet.

I'll be watching these bottles like a hawk and opening one a week, just in case. I would normally never have bottled this high but it's been 20 days, all the yeast had dropped out of suspension and it seems to be done. I've never had much luck getting stuck brews going again, either with extra yeast and/or sugar. I have bottled FG 1020 beers in the past and not had bottles bombs.
 
No, and that kinda surprised me, I was expecting it to be too sweet.

I'll be watching these bottles like a hawk and opening one a week, just in case. I would normally never have bottled this high but it's been 20 days, all the yeast had dropped out of suspension and it seems to be done. I've never had much luck getting stuck brews going again, either with extra yeast and/or sugar. I have bottled FG 1020 beers in the past and not had bottles bombs.

Sounds encouraging. Maybe it’s not your hydrometer that’s suspect - it’s your thermometer! 😂
 
I used it in my Christmas Stout

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It seemed to flatten off after a couple of weeks so I upped the temp and it carried on a bit.
 
Used Empire Ale yeast 3 times now, twice quite recently and once a few years ago. The two recent brews "finished" at 1.021 (OG would have been somewhere around 1.050). The first time it happened of the 2 recent occurrences I put it down to "something else being wrong"...I had a temperature issue during mashing which may have lead to a less fermentable wort. The 2nd time it happened I twigged that there was something else at work (or not at work as the case may be!!).
Checked my brewing records to see if I'd ever used the yeast before and found that I'd used it in a stronger Christmas Ale about 3 years ago which had finished at 1.024 when it should have got down to about 1.018. Did a bit of research and found that it (finishing around 1.020) seems to be a common occurrence with this yeast.

I probably wont use the yeast again but if I did then I'd probably make sure that I'd mashed at a low temperature to compensate for this particular foible of the yeast.
 
Thanks, that's really useful to know that I'm not the only one experiencing this. I have another packet of M15 that is well in date, will try it with a higher OG to compensate plus a cooler mash, perhaps in the Oatmeal Stout I've been planning.
 
I've only ever used M15 in stouts - on three occasions, the most recent being my Christmas Coffee Milk Stout, which is when I began to realise something odd is going on. Each time, the attenuation has been between just 58% and 63%, rather than the 70% - 75% claimed by Mangrove Jack's. FGs have been around the 1022 region. My mash temp in the Grainfather has been 68 degrees for each of those stouts.

To be fair, I've also had the same problem with Fermentis Safale S-04 in dark beers.

I too, will try reducing the mash temp next time around, and/or use a different yeast. Lallamand Nottingham, for example. I may also try to aerate the cooled wort more than normal before pitching.
 
I've had similar with Safale S-04 and dark beers, but not as extreme: 2-4 gravity points higher. Gervin Ale and MJ Liberty Bell are my general go-to yeasts now, but occasionally it's good to try others, hence this experiment with M15. Once I've used the other packet I probably won't buy it again.
 
I've had similar with Safale S-04 and dark beers, but not as extreme: 2-4 gravity points higher. Gervin Ale and MJ Liberty Bell are my general go-to yeasts now, but occasionally it's good to try others, hence this experiment with M15. Once I've used the other packet I probably won't buy it again.
I'll have to give MJ M36 a try. Especially for hop-forward beers. May be a good replacement for US-05, which I've tended to use for pale & hoppy beers.
 
I'll have to give MJ M36 a try. Especially for hop-forward beers. May be a good replacement for US-05, which I've tended to use for pale & hoppy beers.

I am a complete convert to M36. Only recently started using it, been brewing 11 years but this is the first time I've been truly convinced of a yeast making a big difference. I've used it to replace Safale S-04 which was my go-to yeast, but not anymore.
 

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