Lallemand London ESB FG at 1.036?

[BigdogMark]

I've got a porter I fermemented with the Lallemand London ESB yeast with an OG of 1.061 that has stopped at 1.036. The ferment was quick at 65 degrees with two other brews using Nottingham. They both finished at 1.012 as expected. The recipe was

8# Pale Malt
2# Munich Malt
1.5# Crystal 20
1.5# Chocolate Malt
1# Flaked Oats
4oz Lactose
8 oz Malto-Dextrine 5 mins to flameout

Mashed at 154, looking for a full malty flavor but I was expecting it to get to at least 1.024, maybe 1.022. There has been no evidence of continued fermentation, no circulation of the wort and yeast, nothing.

Can I, should I throw in some Nottigham to try and get this to ferment further out?

 

[BigdogMark]

I forgot to add I set up the water profile from RO to Black Full in Brewsmith. The mash had a ph of 5.29 at 30 minutes.

 

[brownni5]

Are you saying this exact recipe has finished at 1.012 in the past? You've got a lot of dextrinous malts/lactose (for some reason) in there that will not ferment very low, and your mash was a little bold given the malt bill, but unless you messed up your mash temp (i.e. read 154 when it was 164), I'd imagine it would finish in the low to mid 1.020 range.

How long has it been fermenting? Before pitching another yeast, I'd let it sit in primary for at least 10 days and try ramping up the temperature. If after that you still have what you feel is an under-attenuated beer, then by all means, pitch a yeast you have more confidence in.

 

[bucketnative]

What method are you using for gravity measurement: hydrometer or refractometer?

If refractometer... then you need to apply a correction factor to your measurement to account for the presence of alcohol. It is not accurate once fermentation has started, and it is intended for use on sugar - water solutions (wort or fruit juice). 1.036 probably corrects to something near 1.012, and your wort is now beer.

If hydrometer... you may need to rouse the yeast and raise the temp a bit.

 

[suregork]

London ESB is unable to use maltotriose. So a standard 1.060 wort with high mash temp is expected to finish around 1.020-1.025. Add in the fact that you also have lactose and maltodextrin in the wort, the high FG is not a surprise.

 

[BigdogMark]

Thanks for the replies and guidance. The porter has been fermenting for 9 days now. This same porter recipe using WLP002 as the yeast fermented out to 1.020 measured with a hygrometer in the past. I use a refractometer on brew day, and a hygrometer for post fermentation readings. I am pretty confident my temps were at 154, not 164 as we weren't drinking during the brew day. I know, sad really. I will raise the temp and try rousing the yeast. Maybe it was just too cool. This is the first time I fermented my brews this cool. I typically have had the room at 69 or 70 degrees, but the new ac will pull the room on down. My other two brews fermented at the lower temp just as effectively as at 70.

 

[Steveruch]

The only time that I've used this yeast was on an extract ordinary bitter that went from 1.040 to 1.012.

 

[thehaze]

London ESB and Windsor both cannot ferment maltotriose, as pointed above. In order to get decent attenuation with these yeast, you need to mash much lower than you did, for a wee longer time and use some simple sugar in the boil. These two yeast, just like their cousing S-33 from Fermentis, are fast and agressive fermenters, that will leave a malty beer behind, without the need of mashing high. I am fan of these yeast, but I never mashed higher than 147F and less than 90 minutes.

Nottingham could take it lower, but how much lower seeing that you mashed fairly high, added some lactose, etc., I wouldn't dare say. Maybe closer to 1.030, which would make for a very sessionable Porter. Cheers.

 

[BrewnWKopperKat]

I am fan of these yeast [London ESB and Windsor], but I never mashed higher than 147F and less than 90 minutes.

Interesting... I've brewed a couple of all-grain batches with London ESB (got "ok" results), but didn't mash that low or that long.

The only time that I've used this yeast was on an extract ordinary bitter that went from 1.040 to 1.012.

roughly 70% attenuation.

FWIW (and reminding myself that OP was brewing all-grain), I stopped using Windsor, London ESB, and S-33 in my extract+steep batches a number of years ago - didn't like the sweetness of the beer.