Mash temperature screw up

[Neptune]

Still pretty new to this... My last batch was a simple amarillo smash recipe and I wanted to mash in at 153.

I messed up my strike temp and ended up in the upper 140's when i was finished mashing in so I put the flames to it until I got up to my desired number (BIAB) and then left it alone and wrapped it in a blanket. An hour later I checked the thermometer and it read 157. I either read it wrong the first time or it kept heating after I covered it all up, I guess.

From what I understand, higher temps make for a sweeter and less fermentable beer... How high is too high? My SG ended up being 1.058. It went off pretty good and built up a nice krausen for a few days and it's settled down pretty substantially already (10 days later). What sort of FG should I expect (S-05 yeast)?

Would dry hopping help offset some of the unintended sweetness? I know it's aroma only instead of bittering at this point, but maybe it would take the edge off?

 

[rhys333]

I usually get about 78% attenuation with US-05. Not sure what to tell you other than let it ride and see what you get. If it stalls out low, say 68% attn and its not dry enough for your taste, you could try adding a little sugar to dry it out a bit. See what happens though. It might work out just fine as is

 

[deepbluegroove]

most of the conversion happens very quickly; I have seen articles say that most of the sugars are converted in the first ten minutes of the mash, so if you were in the 140s, then over time got to the 150s, you probably converted most of the sugars before you got to 157. That being said we can only guess what the US-05 will do with the wort you produced. What did you expect in your SG? was it 1.058? After ten days you probably have reached FG. test it with a hydrometer.

Dry hopping adds aroma of hops. in my experience the hops don't cover the sweet flavor unless they are bitter (boiled in the wort). So a high IBU beer can cover some sweetness of the beer. See the chart in this post:
https://www.homebrewtalk.com/showthread.php?t=123649

 

[tsl346]

The conversion from starch to sugar does happen relatively quickly (mostly in the first 10 minutes or so). But you will continue to turn unfermentable sugars into fementable sugars for 60 minutes and longer. Depending on how long it took you to get up to 157 it might not make a huge difference. For a point of reference when talking a consistent mash temp through the whole mash, with a 160 degree mash for 60 minutes you will produce about 60% fermentable sugars vs at a 150 degree mash you produce about 80-82% fermentable sugars.

 

[bigdaddybrew]

I'm guessing you used a glass candy type thermometer?

 

[Neptune]

Okay so I probably ended up getting some decent conversion at the early stages of the mash. Thanks for the replies about that.

Not sure exactly what the SG should have been. I was sort of following this recipe which says 1.060, but I was using 13 lbs of a local 2-row grain (instead of 12lbs of Maris Otter). I would have guessed it should have been a little higher than my 1.058, but again I don't have a lot of experience with this and I'm still playing with my process.

And yes, I was using a cheap glass candy type thermometer. My first batches I compared it to a couple kitchen thermometers that I have and they all read within a degree or so of each other, so I had a fair bit of confidence in the reading... I'd love to get one of those fancy thermapens one day. It is on the list.

 

[bigdaddybrew]

I have used the glass type themometer and found them slow to react. I tried to add heat to my BIAB mash and I would over shoot every time. I switched to an inexpensive metal stem dial thermometer and it reacts very quickly solving the overshoot. The digital pen type are probably the best balance of accuracy and reponsiveness but I'm too cheap to buy a good one. I calibrate my metal stem thermometer to the glass thermometer at 150f. This has worked well for me.

 

[doug293cz]

@Neptune: If you post as many of the following as you have available, I might be able to estimate your conversion efficiency.

• Grain Bill (done)
• Strike water volume (and temp at which measured)
• First runnings SG (prior to any sparge)
• Sparge water volume + volume measurement temp
• Pre-boil volume + volume measurement temp
• Pre-boil SG
• Post-boil volume + volume measurement temp
• Post-boil SG (1.058?)

Brew on

 

[Neptune]

Thanks Doug... I'm doing BIAB no sparge, but I don't have a lot of the information you're looking for, unfortunately. I do know that I mash in my full 8 gallons (158F this time) and after the boil I end up with approx 5.25 gallons. The 1.058 was post boil.

 

[doug293cz]

Thanks Doug... I'm doing BIAB no sparge, but I don't have a lot of the information you're looking for, unfortunately. I do know that I mash in my full 8 gallons (158F this time) and after the boil I end up with approx 5.25 gallons. The 1.058 was post boil.

Ran a simulation for 13 lbs of 2 row starting with 8 gal strike water and 5.25 gal post boil, and assuming a 1 hour boil (if not correct, let me know.) To get the volumes to work out right, I had to set the boil-off rate to 1.25 gal/hr (reasonable), and apparent grain absorption to 0.115 gal/lb (quite high for BIAB.) If my grain absorption estimate is anywhere close to accurate, you may want to look at either squeezing your bag, or letting it hang and drain for a much longer time. BIAB grain absorption should be around 0.08 gal/lb or lower, but at least less than 0.10 gal/lb.

Given the above, to hit your target gravity I had to set the conversion efficiency to 88%. With good crush, adequate mash time (coarser crush requires more time) and reasonable temperatures, you should be able to achieve 95% or better conversion efficiency. So, it looks like the high temps may have affected your enzyme activity, or your crush is too coarse for the mash duration that you used.

Brew on

 

[Neptune]

Wow, thanks for taking the time to do that... It's much appreciated.

I'm brewing as I type this on my phone paying closer attention to these details. I just pulled the bag after squeezing it pretty good and letting it sit for a while and I'm down to 7 gallons, so I lost a gallon to absorption.

Boiling now, but not as vigorously as last time (which could have been part of the problem). We'll see where I end up.

Thanks again. Cheers!

 

[Neptune]

Oh,that's a slightly different grain bill...

11 lbs 2-row
1 pound wheat flakes
0.5 lbs crystal

 

[doug293cz]

Oh,that's a slightly different grain bill...

11 lbs 2-row
1 pound wheat flakes
0.5 lbs crystal

One gal absorption with 12.5 lbs is right at 0.08 gal/lb. So, that's in an appropriate range.

Brew on