The Boil
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I believe that the temperature of the boil is only one part of the process.
Alpha acids will be isomerised from temperatures below boiling (mash hopping is one method and that's at mash temps around 65).
The motion of a vigourous rolling boil helps break the oils out / down as well. So ... lower temps will work (with less loss of volatile aroma and flavour) but you won't get as much bitterness out for the same length of boil as you would with a rolling boil
Alpha acids will be isomerised from temperatures below boiling (mash hopping is one method and that's at mash temps around 65).
The motion of a vigourous rolling boil helps break the oils out / down as well. So ... lower temps will work (with less loss of volatile aroma and flavour) but you won't get as much bitterness out for the same length of boil as you would with a rolling boil
I suspect you would stilll isomerise the alpha acids but at a reduced rate so you would lose efficiceny. However I would be worried sbout not achieving a good hot break and boiling out some of the volitile components that you dont want in your beer. Also 100degC will ensure your wort is as sterile as you can get it.
No expert but I would stick with a full boil.
No expert but I would stick with a full boil.
What better way to spend a Saturday afternoon than sitting down studying, as chance would have it, Wort Boiling.
The following is a brief extract from the module on wort boiling. The need for a good rolling boil is repeatedly stipulated.
The purpose of wort boiling is to stabilize the wort by:
Killing spoilage micro-organisms.
Reducing the amount of coagulable nitrogen thus promoting colloidal stability.
Extracting the desirable principles of hops to give beer its characteristic aroma and flavour.
Reducing undesirable volatile compounds through evaporation.
Isomerisation of Bitter Substances
During boiling the insoluble alpha acid extracted from hops are converted to a more soluble iso-alpha acid. This reaction is accelerated by temperature. Isomerisation is a relatively rapid reaction with production of over 90% of the wort bitterness occurring within the first 30 minutes of boil. Maximum isomerisation usually occurs within 60 to 70 minutes of boiling and accounts for around 60% of the total alpha acid present. Iso alpha acid continues to be lost during the fermentation and maturation process and is lost in any foam produced so that the final conversion value of alpha acid into iso-alpha acid in the beer is around 40%.
Oh and wort usually boils at 102-104 C depending on how heavy it is.
MHB
The following is a brief extract from the module on wort boiling. The need for a good rolling boil is repeatedly stipulated.
The purpose of wort boiling is to stabilize the wort by:
Killing spoilage micro-organisms.
Reducing the amount of coagulable nitrogen thus promoting colloidal stability.
Extracting the desirable principles of hops to give beer its characteristic aroma and flavour.
Reducing undesirable volatile compounds through evaporation.
Isomerisation of Bitter Substances
During boiling the insoluble alpha acid extracted from hops are converted to a more soluble iso-alpha acid. This reaction is accelerated by temperature. Isomerisation is a relatively rapid reaction with production of over 90% of the wort bitterness occurring within the first 30 minutes of boil. Maximum isomerisation usually occurs within 60 to 70 minutes of boiling and accounts for around 60% of the total alpha acid present. Iso alpha acid continues to be lost during the fermentation and maturation process and is lost in any foam produced so that the final conversion value of alpha acid into iso-alpha acid in the beer is around 40%.
Oh and wort usually boils at 102-104 C depending on how heavy it is.
MHB
B
bindi
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Pressure increases[ brain decreaseskirem said:
diver for 37 years, sorry] volume decreases.Gas law that is <_<
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