whats your attenuation?

[micblair]

Seems that I can rarely crack the sub 1.010 SG mark - even if I use adjuncts. Most of the time my OG is 1.045 give or take a few points. This usually correlates in the mid 70's attenuation wise for yeast strains like Nottingham, US05, 34/70 (irrespective of hydration). However I really want my beers to finish drier and thinner, around 1.008. My mash regime is 62C for 40 mins, 72C for 20 mins and a brief mash out and at least 5 mins O2 at pitching, with ample Ca2+ in the main mash. Thinking of going back to liquid cultures with a cranking starter to see if that makes a difference.

 

[verysupple]

Hmm, it seems like you're doing all the usual things to get the FG down.

However, depending on the malt, 62 C might not actually be high enough for gelatinisation (the VZ45C or Hartong index will give an estimate of the gelatinisation temp - info ). If this is the case, then your grain is gelatinising during your ramp to 72 and you might not be giving beta-amylase much time to do its thing (as it denatures quite quickly at 72 C). I'd try bumping the low rest up to 64 - 65 C and see if it makes a difference.

Your practices seem pretty good so I doubt this is the problem, but the other obvious thing is pitching rate. What sort of pitching rates are you using?

EDIT: Oh yeah, and what's a typical recipe you've had the problem with? There is some debate about whether large amounts of crystal or specialty type malts lead to higher FGs, but it's worth ruling out.

 

[micblair]

In my hands a program mash offers no improvement over a single infusion mash at 65C for 1h (the difference may not be detectable with a $8 hydrometer though). My recipes never contain more than 5% crystal, and most of the time no crystal malt at all, just usually mostly pils. 11.5g pack in 20L

 

[verysupple]

Yeah, single infusion at 65 C would usually do the job.

A single pack of Nottingham or US-05 is about right for 20 L of ale, but you'd want to double it for the W34/70. Although if you've had the problem with the ale yeasts then it's probably not the pitching rate that is causing the problem.

I'm running out of ideas so let's check the usual newbie mistakes. Are your temp probe and hydrometer calibrated?

You said you already tried adjuncts. How much simple sugar did you add? And when you used simple sugar, did you remove some of the malt so that the OG was the same?

 

[mje1980]

I'm kind of sure beta will be active down to high 50's. Not optimal, but active. Certainly active at 62.

I always add a 62c rest for my beers, from 20-60 mins depending and regularly get under 1.010, especially for a 1.045 SG. I like dryer beers so aim for sub 1.010 on pretty much all beers, even malty ones like mild. Ironically I'm trying MJ Newcastle dark ale yeast and despite a low 60's rest, it seems to have stopped at 1.020 .

 

[Spiesy]

I got an amazingly awesome dry APA recently with WLP008, finished at 1008, lowest FG I've ever had a beer finish. All grain. No adjuncts. 64-degree mash. Can't remember what the OG or efficiency was though.

My IPA with the "Super Yeast" WLP090 that is crash chilling, chewed through a lot of malt to give me around 84% attenuation (from memory, I don't have data here). Finishing at 1010 and just a shade under 7% alc/vol.

 

[Spiesy]

Both these beers were grown on starters. Yeast nutrient present. Wort aerated. Fermentation conducted within recommended range.

 

[verysupple]

I'm kind of sure beta will be active down to high 50's. Not optimal, but active. Certainly active at 62.

I always add a 62c rest for my beers, from 20-60 mins depending and regularly get under 1.010, especially for a 1.045 SG. I like dryer beers so aim for sub 1.010 on pretty much all beers, even malty ones like mild. Ironically I'm trying MJ Newcastle dark ale yeast and despite a low 60's rest, it seems to have stopped at 1.020 .

Sure, beta-amylase will be active at those temps, but that's pointless if there is nothing available for it to work on. Gelatinisation makes the starch available for enzymes to work on. No gelatinisation, no amylase activity.

 

[mje1980]

Surely 60c is enough for gelatinisation for most available malted barley? In 10 years of mashing I've never worried about gelatinisation temps with malted barley. I also get plenty of conversion with just a low 60's rest for saisons and other dry beers.

For unmalted cereals yeah, but i do a cereal mash for those with no issues.

 

[verysupple]

Surely 60c is enough for gelatinisation for most available malted barley? In 10 years of mashing I've never worried about gelatinisation temps with malted barley. I also get plenty of conversion with just a low 60's rest for saisons and other dry beers.

For unmalted cereals yeah, but i do a cereal mash for those with no issues.

You're right, most modern barley malts will gelatinise fine at those temps. But the OP hasn't said what he's using so it's still a possibility.

 

[carniebrew]

<snip>
Your practices seem pretty good so I doubt this is the problem, but the other obvious thing is pitching rate. What sort of pitching rates are you using?
<snip>

For what it's worth, this article shows some research into how pitch rate might affect final gravity. Interestingly he found that both over and under-pitching led to lower FG's than pitching the 'recommended' amount. So you might be getting your pitch rates too ummm, right?

 

[verysupple]

For what it's worth, this article shows some research into how pitch rate might affect final gravity. Interestingly he found that both over and under-pitching led to lower FG's than pitching the 'recommended' amount. So you might be getting your pitch rates too ummm, right?

Yeah, I've read that before. It's a good article. It's pretty uncommon for a homebrewer to pitch anything like 4 million cells/mL/P, though, so I never bother asking when people have attenuation issues. Of course this doesn't include pitching an entire yeast cake from a previous batch. But if someone is willing to cut corners like that then low attenuation isn't their biggest problem.

 

[mmmyummybeer]

Awesome Linky verysupple, lots of good info there.
My thoughts -Sounds like your pretty right on mash temps and recipee design and I'm therefore assuming you would be pretty spot on with fermentation temps etc.
You haven't mentioned mash pH and thickness though, just wondering if there could be something there? Like most things brewing there is never one straight answer only a multitude of possibilities.
Any way good luck and I'm keen to hear how you go and hope you find your answer.

 

[lael]

Is this solved? Could be a simple problem... Like a faulty temp reading? Have you checked your thermometer against other ones?

 

[fattox]

I had a good cracker batch of US05 get two different IPAs down to under 1.005, I think one cranked down to 998 even! These both started high 1060's, low 1070's - a Pliny clone and one of my own recipes. Mind you these were over pitched as all hell, a pack each of us05 to a 5 litre batch. I usually have no problem getting under 1.010 though, my bopils got down around 1.002-1.004 if memory serves as well on WY2011 (Urquell lager)

 

[micblair]

You're right, most modern barley malts will gelatinise fine at those temps. But the OP hasn't said what he's using so it's still a possibility.

Usually a selection from Joe White's barley or wheat malt -- nothing out of the ordinary. I'm keen to see if switching back to liquid cultures and having a suitably sized starter solves this issue.

 

[micblair]

Awesome Linky verysupple, lots of good info there.
My thoughts -Sounds like your pretty right on mash temps and recipee design and I'm therefore assuming you would be pretty spot on with fermentation temps etc.
You haven't mentioned mash pH and thickness though, just wondering if there could be something there? Like most things brewing there is never one straight answer only a multitude of possibilities.
Any way good luck and I'm keen to hear how you go and hope you find your answer.

Re Temp's -- I'm letting a BM take care of all the steps, suppose it wouldn't hurt to cross check this against another thermometer to see how accurate it is.
Mash thickness is on the thin side of course with almost a full volume mash 4.5 kg in 23 L (5:1), and Mash pH is within optimal range 5.2-5.5.