Holding temps through a long decoction mash?

So after my first decoction mash I've got a question... how the heck do you keep temps consistent with your plan?

For my first decoction, I did a modified double decoction (along the lines of a Hochkurtz mash), and found myself constantly struggling to keep temps up. It seemed like every time I made it to the end of a step, my temps had fallen so far that my original beersmith calculations were hopelessly off.

My mash tun is pretty decent--a cooler that keeps temps pretty well on a standard 60 to 90 minute mash--but the mash took me 3+ hours, with predictable (in retrospect) heat loss. Ambient temps in the 40s probably didn't help...

I ended up saving it by water infusions and redoing calculations on the fly, but is there a better way? Should I just expect to recalculate as I go on long mashes like this?

Warming everything up would help, I mash over the flame in the kettle.

You might try a heat stick. With my HERMs I use a heat stick to "stir" my mash to speed up step infusions. I also use a cooler.

I suspect you're not doing your decoctions right. If you can hold temps during a regular infusion mash, you should be able to do the same for a decoction mash.

The way I do a decoction step is as soon as I stir in the strike water (or decoction in a multi-step decoction) and equalize the temperature, I pull my thick decoction and get it heating up. The cooler will hold the temp of the mash while this is happening; otherwise all of your regular infusion mashes would be dropping temperature, too. Just seal the thing up and heat up your decoction. If you do 45 minute steps then you should have about 10 minutes to heat the decoction up to your step temp, 10 minutes to hold at that temp, and 25 minutes to crank it up to a boil while you're stirring. Then mix it back into your mash and immediately pull out the next decoction step. If you're running behind schedule when you get there, don't bother with the sacch rest in the middle of the step--just keep heating it up until you've got it boiling. You've got plenty of saccharification going in the mash tun anyway.

On the last decoction step (coming up to mash out) I pull a thin decoction and don't worry about taking it slow. It's already at saccharification so no point in doing that part of it.

weirdboy--Wow, so you're not waiting at all between mixing the previous decoction and pulling the next? That's much more aggressive than my schedule... I was waiting at least 30 minutes to pull the next decoction. How quickly are you done? What's your efficiency like?

I'll probably try that on my next decoction, although I'm also going to wait until it gets a little warmer (or do it inside)!

Thanks for the feedback all.

Yeah I don't understand why you're waiting to pull the decoction. That same time is already built into the process, since you'll spend that heating up the decoction while the rest of your mash is doing its thing. You are essentially doubling (or more) the rest time by waiting.

I haven't had any problems with efficiency. The last decoction mash I did was on a wee heavy, where I had a huge grain bill and had scaled down my efficiency to 65% anticipating a drop in efficiency based on previous experience mashing my big beers on that equipment. Instead, I hit my normal efficiency of around 72% and way overshot my target OG by nearly 20 points. On previous "normal" sized beers I get roughly the same efficiency as usual.