Soft Boil vs. Hard Boil

[philm63]

I use an E-HERMS setup and normally set the kettle element to 80% for the boil which gives me a nice rolling boil. Not “jumping out of the pot” vigorous, and certainly not a gentle roll. I’ll call this a hard boil. For me, a soft boil would be a low rolling boil just above a simmer – gently rolling but not bubbling.

For my heavier styles (larger grain bill, higher density wort) I get around a 1-gallon/hr boil-off rate at 80%, and for my lighter styles (smaller grain bill, lower density wort) I get around a 1.25-gallon/hr boil-off rate using that same 80% setting.

For consistency’s sake regarding boil-off rate and volume predictability, should I boil my lighter styles softer than my heavier styles, or would it be the same as adjusting my equipment profiles (BS2) to account for this slight variation? Is it actually better to boil softer for lighter styles?

 

[DBhomebrew]

Your boil need not roll. A very gentle boil is all that's needed and in some ways may be beneficial.

Post in thread 'Boil Times/Intensity Question and Observation' Boil Times/Intensity Question and Observation

 

[McMullan]

There seems to be a consensus developing that a vigourous boil is unnecessary and a waste of energy. Time boiling is a more relevant factor, in terms of isomerisation of hop acids. I haven't noticed any change in my boil off rate across styles, but if you have on your system you could just save a couple profiles in Beer Smith. I have several from experimenting and using different set ups on my system.

 

[BrewnWKopperKat]

The "Portland AHA conference" reference / content (mentioned in #2 by @DBhomebrew) is also a Zymurgy article.

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Boiling Wort Visual Reference may be helpful in defining "vigourous" boil, "hard" boil, ...

 

[Teufelhunde]

I am at 3800 ft altitude, so my boil temperature is 205.4 degrees. The temperature of a soft rolling boil will be 205.4. The temperature of a vigorous rolling boil will be 205.4. I don't see any difference other than the amount of boil off.

YMMV

Lon

 

[mabrungard]

An important detail is that both mild and strong boiling are still tools that brewers can and should use. A period of strong boiling is probably needed when your grist included a large proportion of pils malt (necessary to strip DMS), but mild boiling is otherwise sufficient. Less heat stress on the wort means that the beer is less likely to prematurely age or oxidize.

If you’re brewing a style that relies on an aged character (like old ale or barleywine), then a long period of strong boiling IS needed to produce that character.

 

[doug293cz]

An important detail is that both mild and strong boiling are still tools that brewers can and should use. A period of strong boiling is probably needed when your grist included a large proportion of pils malt (necessary to strip DMS), but mild boiling is otherwise sufficient. Less heat stress on the wort means that the beer is less likely to prematurely age or oxidize.

If you’re brewing a style that relies on an aged character (like old ale or barleywine), then a long period of strong boiling IS needed to produce that character.

As long as you have a reasonable amount of convection during the boil, the rate limiting step for DMS removal is conversion of SMM to DMS (DMS boils at ~100°F, or 38°C.) This conversion rate is a function of temperature, not boil vigor, so a soft boil is just as effective as a hard boil.

Brew on

 

[Dr_Jeff]

As long as you have a reasonable amount of convection during the boil, the rate limiting step for DMS removal is conversion of SMM to DMS (DMS boils at ~100°F, or 38°C.) This conversion rate is a function of temperature, not boil vigor, so a soft boil is just as effective as a hard boil.

Brew on

Good to know, less heat generated, and less propane used.