The importance of heat stress
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The importance of heat stress
I just wanted to share some anecdotal experience and photos concerning heat stress in the boil.
For a little while several months back when we were still figuring out the LODO process, I was experimenting with longer boils with a higher boiloff rate. I was getting lots of color pickup, and the post-boil wort lost most of the fresh malt flavor that was in the mash. The finished beer also lacked the nice flavor. We then went to the short, gentle boil and saw tremendous improvement - dramatically improved taste, and far less color pickup.
Here's a picture of some pre-boil wort from a few months back:
And here's the same wort post-boil, pre-chilling (so no cold break has formed yet). This was just under a 2 hour boil with nearly 30% total evaporation:
For a little while several months back when we were still figuring out the LODO process, I was experimenting with longer boils with a higher boiloff rate. I was getting lots of color pickup, and the post-boil wort lost most of the fresh malt flavor that was in the mash. The finished beer also lacked the nice flavor. We then went to the short, gentle boil and saw tremendous improvement - dramatically improved taste, and far less color pickup.
Here's a picture of some pre-boil wort from a few months back:
- preboil1_small.jpeg (327.47 KiB) Viewed 13447 times
And here's the same wort post-boil, pre-chilling (so no cold break has formed yet). This was just under a 2 hour boil with nearly 30% total evaporation:
- postboil1_small.jpeg (346.22 KiB) Viewed 13447 times
Last edited by Techbrau on Fri Jul 01, 2016 11:30 am, edited 1 time in total.
If you always do what you've always done, then you'll always get what you've always gotten.
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- German Brewing
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Re: The importance of heat stress
Now, here's some pre-boil wort from a couple weeks ago:
And the same wort post-boil and post-chilling (so there's some cold break clouding the sample). This was a 60 minute, gentle boil with less than 10% evaporation.
This beer is currently lagering, and the wonderfully deep fresh malt flavor is still there. The color lightened during fermentation. Here's a pic of a sample taken from the lagering keg:
The 96/4 baseline recipe from the paper should be incredibly light - check out the pictures Bryan has posted of his helles here: viewtopic.php?f=12&t=11&start=90
If your finished beer (made with the 96/4 or a similar grist) is turning out significantly darker than Bryan's photos, you likely have too much oxygen exposure, too much heat stress, or both going on in your process.
- preboil2_small.jpeg (298.73 KiB) Viewed 13445 times
And the same wort post-boil and post-chilling (so there's some cold break clouding the sample). This was a 60 minute, gentle boil with less than 10% evaporation.
- postboil2_small.jpeg (321.81 KiB) Viewed 13445 times
This beer is currently lagering, and the wonderfully deep fresh malt flavor is still there. The color lightened during fermentation. Here's a pic of a sample taken from the lagering keg:
- lagering.jpg (321.88 KiB) Viewed 13404 times
The 96/4 baseline recipe from the paper should be incredibly light - check out the pictures Bryan has posted of his helles here: viewtopic.php?f=12&t=11&start=90
If your finished beer (made with the 96/4 or a similar grist) is turning out significantly darker than Bryan's photos, you likely have too much oxygen exposure, too much heat stress, or both going on in your process.
Last edited by Techbrau on Fri Jul 01, 2016 8:14 pm, edited 3 times in total.
If you always do what you've always done, then you'll always get what you've always gotten.
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- Braumeister
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Re: The importance of heat stress
For reference, here is a video of my boil intensity.
https://www.youtube.com/watch?v=7yMUYa0-QpQ
Too much intensity:
https://www.youtube.com/watch?v=k8CiVs6kOA8
https://www.youtube.com/watch?v=7yMUYa0-QpQ
Too much intensity:
https://www.youtube.com/watch?v=k8CiVs6kOA8
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- Brandon
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Re: The importance of heat stress
Timely discussion, I listened to this Brew Strong Podcast on Thermal Stress last night:
http://www.thebrewingnetwork.com/brew-s ... rmal-load/
I've been dialing in boil duration and intensity for the past few brews as well.
http://www.thebrewingnetwork.com/brew-s ... rmal-load/
I've been dialing in boil duration and intensity for the past few brews as well.
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