Protein rest temps

I have a bit of a technical question here, why is 122 the magic number for protein rests? I understand what the rest does but don’t know why 122 is the target temp. I’ve read that you can do a rest at up to 130 degrees, is there a noticeable difference in the result between those 2 temps?
As always, any help is greatly appreciated!
Happy brewing!
Scott

Since other enzymes are also working within those ranges you may choose to work at the higher or lower end of the protein rest because of how it effects them as well.

According to Dr. Charlie Bamforth, there’s really no such thing as a protein rest. You’re not breaking down proteins no matter what the temperature. The 122 F is actually a beta-glucan rest. And it is never necessary, if you ask me. It is usually more of a detriment than anything good in my opinion. Skip it unless you have a need to prove this to yourself. As for the exact temperature range, I am not exactly sure but I would guess 130 F is near the upper part while 122 F is the middle.

This is a quote from another forum.
“I have told here several times the story of the PhD Biochemist who gave a lecture on mash biocehemisty to my brewing club. On one slide he had three frames. One showed a bunny with a basket full of brightly decorated eggs. In the second frame was a picture of a fat man with a big white beard wearing a red suit. In the third frame it simply said “Protein Rest”. So that’s the opinion of the experts. Nevertheless, when I omit a protein rest with Maris Otter I get a protein haze that lasts for over a year. Draw your own conclusions, if you can.”

Couldn’t have said it better.