heating fermentation chamber?

StirStarters said:

The problem with the fermentation chamber idea is that you'll probably be measuring the ambient air temp with the controller and that temp could be a good 5 degrees cooler than the fermenting wort. There's some appreciable heat generated during fermentation. I guess you could take a SWAG and set the controller for 76, but trying to control fermentation by measuring the surrounding air temps is tough. A thermowell inside the carboy where you are measuring the actual wort temp is the way to go. Can your Johnson controller handle that?

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dontman said:

A thermowell is in effect even more insulated from the temp of the ferment than the air. The best way to monitor actual ferment temp is to put the probe against the carboy and then insulate it from the air with some sort of insulating tape or bubble wrap. This way you are measuring the temp of the wort not the surrounding or the medium in the thermowell, which gets its temp from the air.

But to answer the original question. Since your controller is double throw, then you can control temp on the heat side by adding a electric heat source. I use the aquarium heater. The controller will "open on fall" when the temp hits a minimal point- meaning that the controller will turn the heater on when it hits a set point.

For the Golden Strong a tendency is to over-delay the temperature rise. After about 72 hours the benefit of raising the temp will be minimal at best. Even though most recipes say to wait until 72 hours to raise the temp. By this point in the ferment most the yeast are no longer producing the esters that so characterize this style. It is best to pitch at 68 and let the natural exothermal reaction raise the temp so that you are at mid-70's by hour 48 at the latest. Belgian yeasts are very low fusel producers so you do not have to worry too much about this. I would expect to max out at 78-80 at the peak. And I" would use the heater to keep it there for 5-7 days and then begin the decline down to a 68-70 condition temp for a month or so.

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dontman said:

Since the ferment will raise the temp naturally just let it happen. It will probably not get too hot on its own. Most I've done have only gone 7-8 degrees above ambient. I seriously doubt you will need to chill it down or slow the process but you may want to prolong it with some heat.

One way I've prolonged this exothermic reaction is by doing a two stage ferment. By waiting for it to reach its peak temp and then adding some more sugar at about 72 hours. This will kick start it and keep it going for another couple days. It will also serve to dry that big beer down as far as possible. I shoot for 07-09.

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chemman14 said:

hmm, OK. The recipe calls for 3 lbs of cane sugar so should i add 1.5 for the boil, adjust the hops accordingly (how do you do this?) and then add another 1.5 lbs at peak fermentation (72 hours, give or take)

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dontman said:

I would all of the sugar at peak of fermentation.

One of the things about sugar and yeast is the yeast actually prefers the simpler sugar to the maltose and will eat that first. This can make the yeast eat less maltose than it would otherwise. Which in turn would raise the FG.

The opposite happens with a secondary addition of simple sugar. Its like the whole there's always room for dessert thing. The yeast will eat as much maltose as it can and then it will all of the sugar. Result - dry beer.

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dontman said:

If you're using BrewSmith or similar you can see what happens to IBU with sugar added during or after boil.

A quick test in my software showed the IBU rising by ~5 by adding the 3 lbs sugar post boil instead of during the boil. So if you have the recipe tuned to an exact IBU then you might want to reduce the hop quantity by some.

I 've never even thought to look at that before. Interesting. I've just built the recipes with the sugar additions marked as after the boil.

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chemman14 said:

I figured out the calculations and I would need about .15 more hops. How do you add the sugar to the fermenter? make a simple syrup and boil then cool and put in the fermenter?

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dontman said:

Exactly. There is another benefit to this. The beer will be a monster fermenter. If you normally put 5.5 in a 6 gallon fermenter you could lose 1/2 gallon to blowoff. Doing it two stage like this you can have 5 G even and then add that other 1/2 gallon with the sugar. Definitely give a good boil to drive off loose oxygen.

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dontman said:

I know I keep revealing this a secret step at a time but the last time I made my Golden Strong I reserved about a quart of wort out of the fermenter and used that to dissolve the sugar into. It worked really great and it stands as one of my best ever batches of beer.

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