Mashing in decreasing range of temperature

Forgive me if this topic has been covered before. I searched and could not find anything...

I was going to attempt a mash in a 5 gallon bucket, but planning for heat loss and starting at a higher temperature, say 160 degrees. What is the benefit of holding a constant mash temp at 153 over having a constant heat loss and hitting all temperatures between 160 and 135? This should have an equal amount of time in the alpha range and the beta range, leading to a mix of fermentable sugars and unfermentable sugars.

I would guess that losing 15-25 degrees of heat over an hour would be about right. I am heating some water to determine the heat loss of the 5 gallon bucket, as I type this. I will post back with the data shortly.

Is there something I'm missing here? Is there a reason why mashing with a constant heat loss wouldn't work?

I'm not an expert, but I see two potential problems right off the bat:

1)If you start too high (160-ish) you run the risk of denaturing beta amlyase before you fall into the range at which it will be active.

2)If you don't start too high you may fall out of active temp range before full conversion takes place.

"
Is there something I'm missing here? Is there a reason why mashing with a constant heat loss wouldn't work?"

Yes, you denature the B enzymes faster at the higher temp. By the time you drift back to the lower temp, nothing much will be happening.

A much better plan it just to wrap that bucket in a sleeping bag or similar insulator. You can also start at a lower mash ratio and then add boiling water periodically to keep the temp up.

Agreed with the previous post. Science and all. That said, I'd be very interested in an experiment using both methods to see how the finished beers differ in gravity, flavor, etc.

Usually people go the other way from 140ish to mid 150s because of what billl said.

http://www.howtobrew.com/section3/chapter14-5.html

Ok, I understand now. So it is better to start at a lower temp and raise it to a higher so that beta amylase is not denatured.

I've got the data from the temperature test on the bucket.

3.75 gallons
Water Starting Temp: 170
Temp After Adding to Bucket: 154
After One Hour: 136

That is a drop of 18 degrees per hour.

Would there be anything wrong with starting at around 147, letting it drop down to 138 (over 30 min). Then raising the temperature to 158, then letting it drop down to say 149? Seems like that would hit both optimal temp ranges of beta and alpha.

The name of the game for mashing is "consistency". I think you'll have a hard time getting consistent results with such large temp swings. A little insulation will go a long way towards narrowing that temp range.

But yeah, you'll get beer with that method. You should consider that the temperature drop isn't linear though. eg if you loose 10 degrees in an hour, that doesn't mean you lose 5 degrees in a half hour. The rate of temp drop is faster the farther you are away from ambient temp.

You might want to test it with a bucket of water with a few blankets tossed over it, see where it's at in an hour. Throw in some rice or oats to make it more realistic. You might be surprised how steady 30lbs of water in a bucket can stay over an hour in a 70 degree room with a few blankets over it, I bet you only lose a degree or two. I've been mashing outside in 30-40 degree weather in a steel pot with a few blankets over it, check it every 20 minutes, usually only have to reheat once to get a couple degrees back. You could just dump in some boiling water to bump the heat up.