2 stage boiling, or how to conserve propane

Kaiser · 01-08-2008, 09:13 PM

While I was searching around again I came across this information about a commercial boiler.

I have been thinking about this too: you could gently simmer the wort for the first 3/4 of the boil time and then give it a good boost for the last 1/4 of the boil. Especially if you could heat only one side or the center of the wort to maintain a good circulation. The latter is needed for the hot break.

The 1st stage will give you the majority of the SMM -> DMS conversion and the later stage will boil it off while using less propane than you would have when maintaining a vigerous boil all the time. it would also lead to less color increase during the boil due to the reduced thermal loading.

I have not tried this, but am intrigued by it since it also means that it would be less likely to boil over in the beginning. And I could even leave the boil pot partially covered for the first stage, saving even more propane.

Just food for thought.

Kai

**Reverend JC** · 01-08-2008, 09:24 PM

Do you not actually need the boiling to put the alpha acids to work from the hops? Will simmering the hops for 45 min give you the same result as boiling them for 45?

**Orfy** · 01-08-2008, 09:38 PM

Simmering a liquid will take it to exactly the same temperature has rapid boiling.
The only thing that changes is the evaporation rate and that is actualy the thing that specifies the boil time.
If you find you can achieve adequate evaporation in less than 60 minutes then you can reduce the flame.

I saving LPG is goal then you can increase the grain and hop bill. Then you can reduce the boil time to 45 minutes.

It would be an interesting calculation to do to see where the best $$$$ utilisation falls. LPG, grain/hops

I have a feeling it will be borderline.

I'll re-read in the morning.

pui.

Kaiser · 01-08-2008, 10:28 PM

Quote:

Originally Posted by orfy

Simmering a liquid will take it to exactly the same temperature has rapid boiling.

Yes, that's what I read as well. Alpha acid isomerization doesn't require the movement of the boil, it mostly needs the heat and still happens during the whirlpool stage (when done hot)

But I don't think that you can reverse it and simmer at at the end of the boil since you might be producing DMS that will not be boiled off.

Quote:

I have a feeling it will be borderline.

I don't think either that it is significant for the home brewer, but it might be worth a try.

Kai

Alamo_Beer · 01-09-2008, 02:30 AM

Quote:

Originally Posted by Kaiser

Yes, that's what I read as well. Alpha acid isomerization doesn't require the movement of the boil, it mostly needs the heat and still happens during the whirlpool stage (when done hot)

Really? I've always heard/read that it's the movement that utilization requires....of coarse what do I know??

Monchoon · 01-09-2008, 05:37 AM

Quote:

Originally Posted by Kaiser

Yes, that's what I read as well. Alpha acid isomerization doesn't require the movement of the boil, it mostly needs the heat and still happens during the whirlpool stage (when done hot)

But I don't think that you can reverse it and simmer at at the end of the boil since you might be producing DMS that will not be boiled off.

I don't think either that it is significant for the home brewer, but it might be worth a try.

Kai

I would think that efficicient hop isomerization would decrease if the wort was not aggitated during the boil ( people who use hop bags or sacks don't get the same efficiency since the hops aren't moving through the kettle)

Also you need the movement for the proteins and tannin to precipitate- hot break

Just some thoughts

**Orfy** · 01-09-2008, 06:10 AM

Simmering will give movement and agitation.

Monchoon · 01-09-2008, 08:03 AM

Quote:

Originally Posted by orfy

Simmering will give movement and agitation.

Yep your right, but will it give enough?

**wilserbrewer** · 01-09-2008, 01:12 PM

I supplement my brewing w/ a heatstick and feel it saves propane, saves time and money, and also reduces stress. (I'm more comfortable doing chores or prepping ingredients running a heatstick than propane flame). I typically use a 2000W element on a 20A GFCI to bring strike water up to temp. as well as assist in bringing to a boil and sometimes during the boil. I have also used it to raise the mash temp. a few degrees by STIRRING the mash w/ the heatstick for a few minutes.

ps. never ever run one dry and always use a GFI

Kaiser · 01-09-2008, 02:33 PM

Quote:

Originally Posted by Monchoon

I would think that efficicient hop isomerization would decrease if the wort was not aggitated during the boil ( people who use hop bags or sacks don't get the same efficiency since the hops aren't moving through the kettle)

Also you need the movement for the proteins and tannin to precipitate- hot break

I do think that you will need sufficient movement, thus the comment to heat on only one side to encurage a good circulation, but I don't think the movement has to be as violent as it is in a 10%/hr evaporation boil. I also thought that isomerizing alpha acids requires wort movement, but then I read that isomerization also happens after flame-out. It might be that getting alphs acids dissolved, before they can be isomerized, requires wort movement.

Kai