US05 question

[micblair]

I'm really weary of re-packaged and re-branded yeast packed from the 500g craft brewer bricks sold by some home brew shops. I'm almost certain that I've noticed a spike in infections and stuck fermentations, (particularly lacto producing diacetyl rich beers) since switching from the 11.5g Fermentis factory packaged yeast which is almost aseptic compared to something that is repackaged under minimal microbiol control.

 

[gilmoreous]

Did you aerate the wort after it cooled?

 

[Kiwifirst]

A bit of anecdotal evidence here, if you'd like.

I've mashed at 72 in the past with a British Pale Mild (sort of a bitter, but not quite). It's the beer that got another member on the AG bandwagon in Brissie.

Used Windsor - a notoriously poor attenuator.

It finished at 1.020.

Hopefully that helps with the 1.030 problem - methinks yeast.

Thanks for this, gives me an answer to what has been bugging me for the last 3 weeks. I stuffed up the temp control of my first BIAG with a British Mild and I couldn't get the OG to drop down anywhere near what I wanted with the 1968 ESB. But I know that I was mashing at around 72 before I realised the problem. I didn't realise that high mash temp could be the reason why I couldn't get the lower FG.

 

[fattox]

The temps are usually around 20-25 degrees when I'm taking a sample. Both my digital temp probes on the outside of each fermenter is reading about 20-21 so samples taken are around there too.

 

[fattox]

Update - both fermenters seem to have fairly well packed it in, and haven't really seemed to have moved gravity. I did pull a 1020 after repitching one but I'm unsure if that was just a fluke so ill retest it when I'm awake. From what I can tell though, the Maris otter seems to have packed it's bags

 

[fattox]

Yep - confirmed both have stalled at 1030. Fired the fridge heat up to 23, repitched fridge temp yeast, gave both a solid swirl. Retested a few days later and nothing has moved despite both having at least 3-400 billion cells of yeast (vastly over pitched) - I think the cold snap without heat gear in that fridge did the batches in. Oh well. Now to grab some more us05 and ferment out my Regal Pale from big brew day

 

[carniebrew]

Strange...a cold snap might drop your yeast out of suspension, but bringing the temp back up, swirling, and adding fresh yeast should definitely get it moving again. It's not as if fermentables become unfermentable due to cold. There's something else going on here, i.e. mash temp or something.

 

[Bribie G]

I know it's probably a bit late in the piece, but you could try repitching with a more aggressive yeast like Nottingham and see what happens.

 

[Pogierob]

A little off topic.
I had a stalled ferment about 5 years ago,
Can't remember the beer but used s-04 from memory.
Fermented at room temp.
After 7 days it stalled at 1.020 and still tasted sweet.
Tested gravity over next 3 days with no change.
Didn't have any more 04 handy so I pitched a coopers kit yeast and went on a week away from home for work.

Got home to find a gravity of 1.012 and thought all good

Bottled as usual and left for a
Month.

It tasted like donkey **** and when I spoke to Pete from BD he told me never mix yeast because they fight each other and create off flavours.

Yet people seem happy to do exactly this here, what am I missing?

 

[Bribie G]

Most of the flavour characteristics of the beer are "locked in" during the first few days of the fermentation - repitching a highly attenuating yeast shouldn't make a huge difference to the intended taste.

Most Coopers yeasts under the kit lids are mixtures of two strains anyway.

 

[CrookedFingers]

Was it the light dry donkey **** you added as an adjunct Rob ?

 

[Bribie G]

I prefer the Dead Dingo's Donger® concentrate.

 

[CrookedFingers]

Hahahaha

 

[wally]

Liquid donkey **** extract is way too meaty.

 

[CrookedFingers]

I find LDDE too ***** forward

 

[Pogierob]

I find LDDE too ***** forward

I thought you were a ***** forward kinda guy though CF.

 

[wally]

You certainly wouldn't want it in the background.

 

[warra48]

OK guys, let's keep this on topic, please.

 

[Cervantes]

I've never mashed higher than about 69 C (except if doing a step mash where some steps are higher) but the difference in FG between mashing at, say, 65 and 68 C hasn't been that big for me. Maybe 3- 4 gravity points. So is accidentally mashing really high, say over 72 or something, going to result in an FG of ~1.030? It seems like a big jump in FG for a relatively small jump in mash temp. I'm just thinking the OPs problem sounds more yeast related than mash temp related to me. There seems to be plenty of info on the effect of mash temp on attenuation, but does anyone have a source I can have a read of that looks at attenuation from really high mash temps? (manticle usually knows of a paper or a book ) Even anecdotal evidence if people have accidentally mashed really high would be good to have a look at.

I've dug out the attached chart (Don't ask me where I got it from) that shows Beta Amylase being denatured at 70 degrees.



So the time at 72 may well result in a much less fermentable wort.

 

[CrookedFingers]

Sorry.
Back on topic.
I have had the same thing happen,US05 stalls out, pitch extra yeast and it fermented out, without off flavours.
I also have had a smack pack not blow up, I pitched anyway, it did ferment out but struggled, took longer than I thought it should.

It could all just be the case that there are just packs of yeast on the market that are not up to scratch.
Not all of their product (whoever the company may be), I'm not saying that, just a pack here or there that isn't as good as all the others.

CF