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Boiling Temps and Tolerance

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Pickaxe

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Just a quick question about boiling temps.

Being a a stovetop brewer I wondered what people's views are on boiling temps. Knowing that water, depending on what is dissolved/suspended in it "boils at different temps, what are people aiming for with brewing?

I would think that 95 - 100 is still boiling given the dissolved sugars at 1040 plus. For hop schedule purposes etc. A rolling boil wont get much more temp really.

Whats the go- rolling boil? Temp boil? What is needed?
 

Lord Raja Goomba I

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My previous stove managed, with the 2 pot system a solid rolling boil. On the weekend, it only attempted to roll, when I covered it (kinda pointless, as most of the evaporation stays in the pot), but was a mild boil otherwise. I still got caramelisation and was still able to get hot break out from a 90 min boil, so I assume from that, it's not too much an issue if it's heavily rolling or just at 100 degrees.

As for hops - my limited research says that minimum temp for isomerisation is 80 degrees C, but that below 100, isomerisation rates rapidly decrease.

http://aussiehomebrewer.com/topic/68163-hop-isomerisation-temperatures/#entry961895

Seems to indicate that below 100 degrees, you halve the effectiveness of hop isomerisation for every 10 degrees below 100.

So 100 is great, below, you won't get the same effect.
 

manticle

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Not so much about the temp, Pickaxe. Above about 80 is enough to see alpha acids isomerise although hotter and moving will be more effective.
Mainly though you need a certain amount of evaporation during your boil to drive off unwanted volatiles and some movement will assist with various other functions including formation and precipitation of unwanted proteins.

Essentially it doesn't need to jump out of the pot but it should be visibly moving or rolling to some degree
 

Pickaxe

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K, thanks guys. Took about an hour for me to get 17L 'rolling' at 100 degrees yesterday. Just wondered whether I needed to or not.

My as well go for 100 if i can. pissweak stove.

Cheers.
 

QldKev

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Have a re-read of what manticle said above. I would also be more concerned about boil off rates rather than temperature.

QldKev
 

manticle

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You can bring up to the boil with the lid on if it helps (as long as you remove it for the actual boil).

Thirsty Boy reported a more rolling boil and appropriate evaporation by floating an aluminium takeaway container on top of the boil so you could try that too.
 

doon

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I sometimes float a containeroin my BM if I have it filled right up. Seems to help achieve good boil and boil off rate
 

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