The importance of heat stress

Times, hopping methods, etc

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Techbrau
German Brewing
Posts: 400
Joined: Thu Oct 15, 2015 1:45 pm

The importance of heat stress

Postby Techbrau » Fri Jul 01, 2016 11:24 am

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:
preboil1_small.jpeg
preboil1_small.jpeg (327.47 KiB) Viewed 1219 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
postboil1_small.jpeg (346.22 KiB) Viewed 1219 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.
Techbrau
German Brewing
Posts: 400
Joined: Thu Oct 15, 2015 1:45 pm

Re: The importance of heat stress

Postby Techbrau » Fri Jul 01, 2016 11:30 am

Now, here's some pre-boil wort from a couple weeks ago:
preboil2_small.jpeg
preboil2_small.jpeg (298.73 KiB) Viewed 1217 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
postboil2_small.jpeg (321.81 KiB) Viewed 1217 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
lagering.jpg (321.88 KiB) Viewed 1176 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.
Bryan R
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Re: The importance of heat stress

Postby Bryan R » Fri Jul 01, 2016 11:43 am

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
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Brandon
German Brewing
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Re: The importance of heat stress

Postby Brandon » Fri Jul 01, 2016 12:31 pm

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.

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