Low attenuation on 30 minute mash?

[worlddivides]

So on a total whim, I decided to just throw a recipe together and experiment with 5 different things all at once. I just did a SMaSH. And 2 of those things I wanted to try were a 30 minute mash and a 30 minute boil, both things I had never done before.

I was very impressed with how, even though the mash was only 30 minutes long, I overshot Brewer's Friend's estimated OG by 5 points. It estimated my OG would be 1.041, but both my hydrometer and refractometer gave me a value of 1.046. I was also impressed by just how much shorter the brew day was as a result.

I fermented with US-05, which is easily the yeast I've used the most over the years. And it has a notoriously long lag time, but this was the slowest start I've ever had with it. With a lot of yeasts I'll get airlock activity within 4-8 hours, but with US-05, it's not unusual to not get any airlock activity until 24 hours later. This time, though, it took between 40 and 50 hours before I got any airlock activity.

About 10 days after pitching the yeast, I took my first hydrometer sample at exactly 20C / 68F, and it's 1.014. That's only 69% attenuation, which is by far the lowest attenuation I've ever gotten with US-05. I mashed at 66.6C (just slightly under 152F). I usually get 78% to 86% attenuation with US-05, so I have to wonder if the abbreviated mash is the cause for the 69% AA. The last beer I fermented with US-05 was mashed at 67.1C (around 153F) and it had 78% apparent attenuation. I had expected something around 1.010 with this brew, so 1.014 was a bit of a surprise.

Now, I'm not complaining. The sample tastes great. Exactly what I was shooting for in flavor and mouthfeel and it isn't even carbonated or conditioned yet. And the 4.2% ABV is only 0.2% below what Brewer's Friend estimated (since it assumed an OG of 1.041 and an FG of 1.008 for 4.4% ABV), so it's not a problem at all. And I'd prefer it to be lower than a lot higher since I didn't exactly want a 5% ABV.

Still, I'm wondering why this happened. I had thought that a 30-minute mash might result in a lower OG, but I never expected it might result in a lower FG. Is low attenuation a known side effect of an abbreviated mash?

 

[dmtaylor]

Mash time is a tool in the toolbox. You can still make good beer with a short mash, as you discovered. I ran a series of experiments 20 years ago with mash times. In brief, I discovered that mash time had a far greater impact on attenuation than efficiency. A mash time of 30 minutes provides adequate attenuation about half the time. The other half of the time, attenuation is low, as you have observed. Mashing for about 35 minutes alleviated most problems, but I determined (more than 20 years ago) that if I mashed for at least 40 minutes, then attenuation comes out perfectly normal for me on my system. I've been mashing most beers for 40-45 minutes ever since. Hundreds of batches mashed for 45 minutes or less. My beers turn out pretty good, and occasionally have won medals. YMMV

 

[Brockness Monster]

What were the other 3 things you changed?

 

[worlddivides]

Mash time is a tool in the toolbox. You can still make good beer with a short mash, as you discovered. I ran a series of experiments 20 years ago with mash times. In brief, I discovered that mash time had a far greater impact on attenuation than efficiency. A mash time of 30 minutes provides adequate attenuation about half the time. The other half of the time, attenuation is low, as you have observed. Mashing for about 35 minutes alleviated most problems, but I determined (more than 20 years ago) that if I mashed for at least 40 minutes, then attenuation comes out perfectly normal for me on my system. I've been mashing most beers for 40-45 minutes ever since. Hundreds of batches mashed for 45 minutes or less. My beers turn out pretty good, and occasionally have won medals. YMMV

That's fascinating. The mash itself was probably around 35 minutes long because I didn't actually start the timer until I added the crushed grains and made sure that all the doughballs were gone (which took longer than usual because there were a ton of doughballs), but it looks like it resulted in REALLY good efficiency but the lowest attenuation I've ever had with US-05. To be honest, the 1.014 FG isn't awful and the beer tastes great, but it was just utterly unexpected.

I think the next time I want to do a shorter mash and boil, I'll probably do a 40-45 mash and a 30 minute boil. I still probably will keep doing 60 minute mashes and 60 minute boils for most beers, but this experiment has already shown me that the abbreviated mash and boil can create excellent-tasting beers.

 

[worlddivides]

What were the other 3 things you changed?

Those are the only 2 things that I can imagine would affect attenuation. As just one of the other 3 things, I utilized advice in another thread for using an aquarium pump in a cooler filled with water (that I later added ice to) hooked up to wort chiller for chilling the wort (it cooled the wort down to about 100F or so much faster than my usual method, but I was unable to get it below 82F when my usual method typically gets me down into the 60s, so I took some of the advice from the other thread and devised a new method that should work better next time).

 

[Brockness Monster]

I've done 30 minute boils my last two batches, which are both still in the fermenters. The wort came out just as clear as before, and I don't do alot of beers with high IBUs, so I will probably keep doing that (unless I pick up some DMS on the finished product). I also want to experiment with 30 minute mashes, but I have been using Belgian pilsener malt that has a lower diastatic power. My plan is to switch to German pilsener malt and try out some 30-45 minute mashes.
I suppose it could be possible that you got some tired or stressed out yeast, a longer lag phase could indicate something along those lines.

 

[worlddivides]

I suppose it could be possible that you got some tired or stressed out yeast, a longer lag phase could indicate something along those lines.

That's possible, but the expiration date on the pack was 2027, I stored it in the refrigerator since it arrived, added yeast nutrient to the boil, and pitched it in the low 70s, so it'd have to be something wrong with the yeast pack itself. I actually bought 2 packs of US-05 at the same time, and according to my notes, the other pack of US-05 had a lag time of 24 hours, which is pretty typical for the yeast in my experience. Although I bought both packs at the same time from the same place, I do think they had different expiration dates, so it's possible something might have happened to the one with the long lag time before the seller got it. Maybe it's impossible to know at this point. It looks like the short mash is probably responsible for the lower attenuation, even if the long lag time had nothing to do with the short mash time.

 

[hottpeper13]

I've noticed more malt flavor when I do a 45 min mash and boil. When I Gypsy brew I do this and mash at 154, pitch Notty and it takes a 1.044 down to 1.012. It's my best bitter recipe that I make so I can pitch the cake on my RIS. Ditch the US05 and pitch Notty.

 

[worlddivides]

I've noticed more malt flavor when I do a 45 min mash and boil. When I Gypsy brew I do this and mash at 154, pitch Notty and it takes a 1.044 down to 1.012. It's my best bitter recipe that I make so I can pitch the cake on my RIS. Ditch the US05 and pitch Notty.

I use Nottingham for English IPAs, bitters, and imperial stouts, but I've never used it for an American-style beer before (I actually have a packet of Nottingham in my fridge right now). Although it is pretty neutral, it still tastes "English" to me, and I wouldn't want to use that for, say, an American Pale Ale or a West Coast IPA (though I do know that some people do use Nottingham for that). Both Nottingham and S-04 start fermenting very quickly. I use S-04 mainly for English-style stouts, porters, brown ales, and so on, and I get airlock activity usually within 4 hours. But... even though I've heard of people using S-04 in New England IPAs or Nottingham in West Coast IPAs, I have difficulty imagining doing that myself.

Besides, US-05 only has a long lag time at the start. It still finishes fermentation about the same time as most other yeast strains.

 

[hottpeper13]

I start my fermentations at 55*, set to 60*, raise to 64* at day 3-5 depending on OG. I don't get any English flavors at all with this schedule. The yeasts I use in this fashion are Notty, BRY-97,2565, 2575, 1007 all very clean.

 

[jdauria]

What was your mash temp? I feel like I just listened to a Brulosophy podcast where they were talking about aattenuation with "short and shoddy" mash. Something about not enough time at beta and alpha rests, where the higher alpha mash temps (say 158F) will create a less fermentabale wort, leaving a fuller body beer, while a lower beta mash (144-152) will give you more fermentable sugars and higher attenuation, but a dryer and thinner beer. If you did a single mash step, maybe consider doing something like 144 for 15 mins and then 156-158 for 15 minutes (basically a Hochkurz mash but shorter periods) to get a better blend of fermentable and unfermentable sugars.

Surprised that you overshot gravity. Did you adjust your efficiency for the shorter mash? Again I know the Brulosophy guys with their short and shoddy brews usually lower their efficency somewhere between 50-60%. The one time I did a 30/30, I want to say I got something like 61% effciency vs my normal 70%.

 

[worlddivides]

I start my fermentations at 55*, set to 60*, raise to 64* at day 3-5 depending on OG. I don't get any English flavors at all with this schedule. The yeasts I use in this fashion are Notty, BRY-97,2565, 2575, 1007 all very clean.

I've never fermented Nottingham below 60F, but I guess it does have an insanely wide fermentation range listed on the package, going from lager territory (50-60) straight up into saison territory (77 being the top temp listed). I've mainly fermented it around 64 to 67 or so, and it's definitely a clean yeast, no question about it. I might eventually try it on an American style just to see.

 

[worlddivides]

What was your mash temp? I feel like I just listened to a Brulosophy podcast where they were talking about aattenuation with "short and shoddy" mash. Something about not enough time at beta and alpha rests, where the higher alpha mash temps (say 158F) will create a less fermentabale wort, leaving a fuller body beer, while a lower beta mash (144-152) will give you more fermentable sugars and higher attenuation, but a dryer and thinner beer. If you did a single mash step, maybe consider doing something like 144 for 15 mins and then 156-158 for 15 minutes (basically a Hochkurz mash but shorter periods) to get a better blend of fermentable and unfermentable sugars.

Surprised that you overshot gravity. Did you adjust your efficiency for the shorter mash? Again I know the Brulosophy guys with their short and shoddy brews usually lower their efficency somewhere between 50-60%. The one time I did a 30/30, I want to say I got something like 61% effciency vs my normal 70%.

66.6C (151.88F). Considering the apparent attenuation was 69%, I don't think I'd want to put more unfermentable sugars in there.

I also was surprised that I overshot the gravity. I did not adjust my efficiency for the shorter mash. I kept it set at 70%, which is normally what I hit, but the 1.046 I got was more like 80% efficiency. I was expecting to take something of a hit and get maybe 60% or 65% efficiency.