Biab mash temperature limits

[clarkeuk]

Just done a trail run with my boiler bringing it up to mash temp 67 degrees and insulating the boiler I had a 2 degree drop after 60 mins and 3 degrees after 90 mins ( 1 degree per 30 mins) is this a acceptable heat loss or do I need more insulation or turn the heater back on
thanks again

 

[keat64]

I did my first AG about 6 weeks ago.
I royally screwed up with the mash temps.

I struck far too hot, then not realising that the thermomemer had a little lag, and in a blind panic I added too much cold.
This left me with a mash temp of only 59°C.

At this point, i wasn't sure if i should add more hot, or leave it to mash longer, so I posted on here.
30 minutes later, i got the answer i needed "Add more hot", so i boiled a kettle and managed to raise the temp to 64.9°C.

My 64.9° held constant for an hour, and my beer eventually turned out fine.

so in answer to your question, after my war and peace essay, you'll probably get away with it.
I have heard tales of BIAB brewers giving the heat a little boost.

 

[Tony1951]

It's surprising how tolerant mashing beer can be. My first efforst were a mixture of panic and terror as just like Keat64, I over-reacted to a high temperature and over cooled and then had to run around looking for kettles of boiling water. Got away with it every time, though sometimes the beer was a bit sweeter than others when I overdid the heat.

I like some residual sugars in my brews if I can get them and aim for 68C - 69C at the start of the mash, but probably most people aim to get about 64C - 65C.

I've had mashes ending at about 62C at the end of the hour.

It is pretty much standard thinking that most of the starch conversion happens in teh first ten minutes or quarter of an hour, so I wouldn't be worrying much about a few degrees drop off at the end of an hour if you started at about 66C.

I have found a strike temperature calculator like this one is really useful:

http://www.jimsbeerkit.co.uk/calc.html

Measure grain mass and grain temperature accurately as well as the volume of strike water and you can hit an exact start temperature with that calculator. REALLY useful I think.

There are some other great calculators on that page for brewers.