High FG using London Ale 1028 twice

[NavyChief]

Ok, so twice in a row now I have used Wyeast 1028 for London Ale and finished with a high gravity.

The first one was an Imperial Stout with an OG of 1.072. I used two smack packs of 1028. FG was 1.036. I had rapid fermentation within 24 hours and had blow-off for two days. Fermentation slowed after that. After 1 week fermentation had all but ceased and I moved it to my secondary. I left it in the secondary for a week and bottled. Temperature for fermentation was in the low 60's F the entire time. Now it is aging in the bottle at 68°F.

My second is a Holiday Stout. OG was 1.076 and I moved to secondary today. SG was 1.040. Fermentation temp was between 63 & 64°F. I added a quarter packet of American Ale yeast to try to get fermentation restarted and moved out to another room where the temp is 68°F. Hoping fermentation restarts.

So, any ideas why I am getting such high gravities?

 

[Beernik]

I've had problems with London III - 1318 but not London - 1028.

What is your mash temp?

 

[NavyChief]

Beernik my mash temp was 160. Pitch temp was 70°F.

 

[Beernik]

You're mashing too high. That's optimum temp for producing dexterins and few fermentables.

Try mashing at 150F. That produces a good mix of dexterins and fermentables. That's my upper limit for London III unless I'm doing a sweet stout. But London III is also a lower attenuator.

 

[pdxal]

High mash temp, as mentioned before was the major part, but there are several other things to learn from.
Short period in primary and transferring to secondary removes the fermenting beer from a large amount of yeast that can still attenuate and clean up off flavors. Many never use secondary for that reason with good results. At least make sure that you have a stable gravity for several days before considering secondary.
Underpitching impairs fermentation, and the stout should have had 2.6 packs of yeast produced yesterday or 3.3 packs of yeast produced a month ago. Better still to make starters with your liquid yeast, they're easy.
Temperature control would help too, and low 60s is in the lower end of the yeast's range. If you have a stalled fermentation most would advise warming up the fermentor before anything else as you did with the second beer. If there are any gravity points left in the first you could end up with bottle bombs since they're conditioning at a warmer temp.
I hope the beers turn out for you.

 

[jglazer]

Oh and oxygenating your wort will help lower that a lot as well. Especially when you have higher gravity beers

 

[aiptasia]

Underpitching yeast without doing a starter, no yeast nutrients, no oxygenation, brewing beers with plenty of unfermentable sugars and a high mash temp. This.

 

[NavyChief]

Thanks all. I am brewing an IPA tomorrow (last brew day of the year) and made a yeast starter this time. I have been using the smack packs and relying on them to do their thing.

My first batch of beer I ever made went really well. It was just dumb luck I guess. I have been trying to follow the same methods for all my beers but it isn't working.

I read and I learn and I experiment.