Rolling boil or vigorous boil?

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I think that a more vigorous boil will result in a higher boiling rate. You cant achieve more than 100 degrees C in a boil so if you're putting more energy into the boil then the way that the additional energy input is being dealt with is with a more vigorous boil i.e. a higher rate of conversion of liquid to gas. If I've ended up with a pre boil gravity a couple of points below target I've sometimes achieve a more vigorous boil to achieve a higher boil off rate so my post boil gravity is about there or spot on. Sometime at a sacrifice of a bit of volume but if the reason for my lower pre boil gravity is due to a slightly higher pre boil volume then it might work itself out.
 
Some brewers advise a rolling boil others a vigorous boil. Which advice should I follow?
Something that you will have to work out for yourself. Apart from alpha acids being isomerised, concentration of the wort, inactivation of residual enzymes, sterilisation of the wort, precipitation of unwanted proteins and removal of unwanted volatiles.
The last two needing vigorous movement of the wort which on a home brew scale means vigorous boiling.
Some people will simmer with lid partially on, (I think a 12.5% of the kettle needs to be open to remove the steam) some will simmer for 30 minutes and boil hard for 30 minutes. Personally I boil hard for one hour.

Precipitation of unwanted proteins. What you don't want in the fermenter.
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You can also do no boil. Just pasteurise at about 80C. Or raise to 100C and switch off.

I do short boils. Save energy and reduce costs. Usually 30 minutes but I'll likely reduce to 20, which I have done successfully before. I leave it to stand til at least an hour is up. The temperature doesn't drop very much and isomerisation of hop acids continues. This method produces beers identical to beers that have a full one hour boil, so far as I can tell. The no boil beers are different. More grainy tasting, less clear.
 
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You can also do no boil. Just pasteurized at about 80C. Or raise to 100C and switch off.

I do short boils. Save energy and reduce costs. Usually 30 minutes but I'll likely reduce to 20, which I have done successfully before. I leave it to stand til at least an hour is up. The temperature doesn't drop very much and isomerisation of hop acids continues. This method produces beers identical to beers that have a full one hour boil, so far as I can tell. The no boil beers are different. More grainy tasting, less clear.
I've only ever done 1 no boil brew. I actually found it way harder to do than normal beer. Tasted very unusual and I wasn't sure I liked it but others did.
Now the dreaded 30 minute boil has been brought up I expect this thread to be shut down before long...
 
I've only ever done 1 no boil brew. I actually found it way harder to do than normal beer. Tasted very unusual and I wasn't sure I liked it but others did.
Now the dreaded 30 minute boil has been brought up I expect this thread to be shut down before long...
Indeed. The OP wasn't even asking about boil time, or simmer, or no-boil. 😞
 
I've only ever done 1 no boil brew. I actually found it way harder to do than normal beer. Tasted very unusual and I wasn't sure I liked it but others did.
Now the dreaded 30 minute boil has been brought up I expect this thread to be shut down before long...
What's dreaded about it?
 
I do 20 min, ha! No whirflock, no gelatin, no cold crash and a crystal clear beer. Except my tries with Kveik, never got clear... I just filter it with a hopbag while transfer to fermenter. Actually I didn't bother too much with it. But... I open my beers at least two months after brew day. Maybe that's the "secret", hehe.
 
Well the other day i did, no boil no hops no electric or gas no stirring no nothing, just sanitise the fv dump in the fresh wort chuck the yeast in and close the lid took 20 miniutes, it is now bubbling away nicely, what it will taste like i will let you know
 
Not to be controversial or a bluff old traditionalist or nuffink, but what happened to the 90 minute boil?
 

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