Mash Temps for 20kg+ grain

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Vossy1

Mash Temps for 20kg+ grain

Post by Vossy1 » Fri Dec 28, 2007 8:56 pm

Can any of the guys who mash with 20kg+ let me know how it affects your strike temps?
Do you lower the strike temp by X amount as compared to popular software ?

EDIT, I'll qualify that question :roll:

I've been finding with 15kg grain loads that the strike temp as calculated by beersmith and promash is too high, on average by 4 deg c.

I did adjust the parameters to suit my system on the software options.
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brewzone

Post by brewzone » Mon Dec 31, 2007 9:55 pm

Made a barley wine strength lager about a month ago with 25kgs of pale malt and a few half kgs of speciality malts giving 26.5kg total. Used 58 litres of liquor at 75 degrees C and it was spot on at 65C once it was all mixed together. No insulation on the mash tun or tubing and the mash tun wasn't preheated. Maybe that is why it came out just right. I'm interested to know whether You preheat the mashtun or not?

Have a good newyear
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RabMaxwell

Post by RabMaxwell » Mon Dec 31, 2007 10:14 pm

That looks about right with my system i normally have my strike water in my mash tun at 76oc for 66oc mash temperature. My grain isn't kept warm i lower my strike temperature to nearer 72oc in the summer months
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Vossy1

Post by Vossy1 » Mon Dec 31, 2007 10:40 pm

Welcome back RM :wink:

I'll have to put these anomolous results to one side for the moment.
On my last brew I used 15kg of grain liquor of 74 deg c (strike @72 in tun) and ended up with a 69 deg mash.
I triple checked the mash temp and it was right. The liquor was double checked via the PID/ thermocouple on the HLT, and using an alcohol thermometer in the tun :?
The grain was at 20 deg c.

I don't pre heat the tun and it's stainless.

Obviously the figures are wrong...I just can't work out where. Maybe there's a cumulative error in 2 places.
Other mashes have been pretty 'normal' but one or two have been strange :?
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RabMaxwell

Post by RabMaxwell » Tue Jan 01, 2008 12:03 am

One thing i noticed when i heat my strike water in my mash tun is i can get widely misleading temperature readings from my NTC probe from the bottom of the tun to the top. I usually start circulating using my Totton pump when i start nearing 76oc to give a more even accurate temperature. Your grain temperature could be the difference my grain temperature will probably be 10 - 15oc at most in winter
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Vossy1

Post by Vossy1 » Tue Jan 01, 2008 12:18 am

I totally agree Rab. I start recircing the HLT liquor a full 10 minutes before transfering to the tun.
Initially there's a drop of at least 5 deg before the PID kicks in and an 'equilibrium' is reached.
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