Questions on time span for isomerization of alpha acids and stability of iso alpha ac

[Finlandbrews]

I want to understand how do we explain that alpha acids convert into iso alpha acids at a different speed? What I mean is why some alpha acids become iso alpha acids after one minute of boiling while others become alpha acids after 10 minutes, 30 minutes, 45 minutes, and so on...?

I also want to know once an alpha acid has converted into iso alpha acid, if there is any transformation of that iso alpha acid during the boil depending on the length of time the iso alpha acid will be under boiling conditions?

I know there are different iso alpha acids too, do we know their stability (capacity of not being transformed) under boiling Conditions and oxygen?

Cheers

 

[brewerdoc]

I want to understand how do we explain that alpha acids convert into iso alpha acids at a different speed? What I mean is why some alpha acids become iso alpha acids after one minute of boiling while others become alpha acids after 10 minutes, 30 minutes, 45 minutes, and so on...?

I also want to know once an alpha acid has converted into iso alpha acid, if there is any transformation of that iso alpha acid during the boil depending on the length of time the iso alpha acid will be under boiling conditions?

I know there are different iso alpha acids too, do we know their stability (capacity of not being transformed) under boiling Conditions and oxygen?

Cheers

It was always my understanding that there are many factors which will alter this conversion such as pH, molecular weight of the alpha acid, the composition of the rest of the solution.

I dont have a great answer as to why this molecule with a molecular weight of this converts at this rate and another takes longer or shorter so I'm sorry I can't be a lot of help.

I found this preview on google which is quite an interesting read in the 20 minutes I have been reading it thus far. I'll keep looking it up and if I find more exact answers to your questions I'll b sure to post.

https://books.google.com/books?hl=e...QQhqRM4A9sSXGmMihms#v=onepage&q=alpha&f=false