Temperature all over the place

[Turricaine]

So this is a brew day I was looking forward to. My 3rd ever AG attempt. I had calculated the US-UK ale on Promash according to my in-house feedstocks.

8.25 LB Pale Ale Grain
250g Crystal Grain
270g Flaked Maize

The problem was during the mash my thermometer reading was all over the place. I put this down to there not being enough water in the boiler since when I used another gallon in my last batch (3 gallons as opposed to 2), everything worked out fine.

2 oz 4.7% AA Hops EKG (Bittering + Aroma)
Gervin Ale Yeast

My question is this: My thermometer reading was too low and then I got suspicious and moved the thermometer to a different part of the grain bed and the temperature reading shot right up. The reason I was worried is that enzymes die above a certain temperature. But if the thermometer did not read it right at the beginning, I am assuming that not all the enzymes were killed. As soon as I noticed I switched the heating off. But it is difficult to do the mash with only 2 gallons of water and a heavy grain bag.

I'm gonna have to put it down to experience.

 

[Turricaine]

Hmm the guy on this link tends to do things very similar to myself:

http://homepage.ntlworld.com/jim.dunleavy/recipe.htm

I think if I had of seen this previously i could have helped prevent my errors from occuring. Unfortunately harsh learning experiences are what happens when you go straight in at the deep end.

 

[uglygoat]

where was the reading lower, and where was it higher? does that mash tun continue to heat the mash whilst it's resting, or do you turn it off? does it have a lid?

 

[Turricaine]

Well I was heating my wort with the grains in a grain bag. In the grains the heat was ~62C whereas the water running around the edge by the heating element went up to 80C by the time I noticed. I think it will turn out 'ok' but I was rather ****ted off by the whole thing (xcuse language).

My boiler is such that when I reach the desired temperature, I turn down the knob until I hear it click to maintain that temperature.

Notice that the guy in the link (exact same hardware as myself except for the wort chiller), does the mash with the grains in-situ and only uses the mesh bag for sparging. I read somewhere that this is the right thing to do if you are using an external heat source (a stove), but leads to scorching in this particular set-up.

All that it means is that I will be using 3 gallons of water in the mash and >2 gallons to sparge to get my >5 gallons wort. I will be using 3kg bags of pale ale malt and then whatever adjuncts on top, but I will avoid using heavy grain schedules as I think this makes matters a bit more difficult for more than one reason.

 

[uglygoat]

you might have a hard time getting a thorough mixing of the mash by keeping the grains in the bag in the mash tun. i think you really want that water around the edges of the grain in the bag to be mixed into the grain.

do you stir the grains at all in the bag?

no lid then eh?

 

[Turricaine]

Here is a pictorial for you to see:

http://i14.photobucket.com/albums/a329/CentralAsia/Aug1724.jpg
http://i14.photobucket.com/albums/a329/CentralAsia/Aug1725.jpg
http://i14.photobucket.com/albums/a329/CentralAsia/Aug1726.jpg
http://i14.photobucket.com/albums/a329/CentralAsia/Aug1727.jpg

As you can see the grain bag goes horrible brown color like soiled underpants. But the real problem is that under gravity without water underneath to support it, the weight of the grain bag means that it sinks deep into the bucket. Fastening the string cord securely does help matters though.

I think one of these stainless steel false bottoms could help matters.

http://www.northernbrewer.com/pics/fullsize/stainless-false-bottom.jpg

Hopefully things will sort themselves out on their own but if it continues to be a nuisance then I will resort to this.

Yeah, I do have a lid. Luckily it is pierced with a hole that allows me to insert a digital thermometer. I aim to put the water in cold and heat it to 65C and maintain it there as a compromise for both alpha and beta amylase enzymes.