How do you aim your mash temp after taking into account loss during mash?

[Coxy]

So for the last 6 months or so, I've been doing a HERMS, so temp loss has been less of an issue for me than it was before. However, I recently did a no-sparge, no-recirc brew just to see how easy it is in comparison. It definitely required less time and less cleaning, and I managed to do a brew mid-week, which I wouldn't usually attempt.

I recorded some data on temp loss of the MT during mash, and turns out it's fairly linear in my case. See chart below.

Now in this case, It dropped about 3C linearly over 60 minutes (it would be good to improve this, clearly).

The question I have, is if trying to get the body of a 65C mash, and I have knowledge that it will drop linearly like this over the period, is it best to start at 68 and drop to target by the end? Start at 67.5 so the average is the target? What do the rest of you do around this (those who have temp loss)?

 

[Crusty]

I wouldn't be starting it at the higher temp as conversion will start almost immediately & you will get extraction at those higher temps until you get to your target. The majority of conversion will take place in the first 20-30mins so according to your graph, you'll be almost done when at 64-65deg anyhow.

 

[Coodgee]

as I understand most of the conversion occurs in the first 30 minutes so I would probably go 66-65 as the starting temp. Others will have a much better idea though.

 

[good4whatAlesU]

Good data. Would be interested in doing this on my set up too.

 

[Liam_snorkel]

have a read of this. http://braukaiser.com/wiki/index.php?title=The_Theory_of_Mashing
Beta amylase activity increases with temperature up until the point of denature, so the higher you are within its range, the faster conversion will happen, leaving you with less fermentable wort. Going by the rough charts in the Braukaiser link you could expect conversion to be effectively done in the first 10-15mins at 68.
It might be best to look at better insulating your mash tun. Some people have success by laying a sheet of bubble wrap on top of the mash (if you have a lot of head space in there)

 

[Coxy]

Cheers all. Some good advice.

@Liam_snorkel better insulation of mash tun is a WIP. I currently have some reflective insulation strapped to the outside of it as well as a piece stuck on the lid. There is still a reasonable amount of exposed SS via thermowells, ball valves, etc, that I can't do much about. See pic of MT below. I will, of course, accept any advice on insulating it better than currently, short of tossing blankets over it.

 

[pcqypcqy]

Have you done the bottom as well?

If you want additional, some cheap kmart yoga matts for the outside should help.

 

[Coxy]

I have not done the bottom, no.. I should probably just sit the whole thing on a sheet of insulation rather than up on wood. It's probably losing most through there.

 

[Liam_snorkel]

throw a sleeping bag over the whole thing during the mash, and loosely tie it at the bottom, same as most BIAB brewers do.

 

[MHB]

The idea that most of the conversion happens in the first 10-15 minutes can be very misleading.
Chopping starch so that most of it is smaller than 20 glucose units long (mainly Alpha Amylase activity) will make it soluble, having a wort that is as fermentable as you need to make beer takes a lot longer.
Alpha makes lots of ends, beta chews on one end making Maltose, without the Alpha chopping up the very long chains the Beta would take a hell of a long time to get through the starch.
So yes the starch may be soulalibised pretty quickly - but it isn't in the form we want.

The other point is that once denatured enzymes don't reactivate when the temp falls - they are dead!
There is a lot more Alpha than Beta available and Alpha works from 50oC on up to the point where it is denatured, Beta is much more fragile.
You would be way better off heating the mash rather than trying to manage what happens as it cools, can be as simple as hot water additions.

I'm about to go and keg a little 1.045 Farmhouse, first brew on a new system, Isothermal mash started at 65oC, it has finished at 1.000 with dry Bell Saison yeast (not exactly where I wanted it), next time I will mash in 3-5 degrees hotter, encourage more Alpha slow down the Beta and get a bit more body in the beer, so its more like the moderately alcoholic summer quaffer I was looking for.
Mark