Temperature drop during Mashing

[Swifty]

I'm having trouble with holding the temperature during Mashing. I use a 20L esky and on the weekend did an all-grain with about 5kg of grain. Now admitedly I used a bigger ratio than I should've but didn't think it would be too bad. I heated about 15L of water to 74 degrees and got a strike temperature of 65 degree's which is exactly what I was aiming for. After 30 min's though it had dropped to 63 degree's so I added 1.5L of boiling water and stirred only to find the temperature was still 63 degree's. I thought I'd leave it and deal with the drop. Fifteen minute's later it was down to about 62.5 degree's though so I added another 1L of boiling water and again it did nothing. Well maybe it got to 63 degree's but it basically did nothing. Sorry for the long rant but what do you think my problem is?? I thought Esky's where supposed to retain the heat well, did I use too much water??

[Aussie Claret]

Swifty,
There are esky's and then there are esky's, the cheaper ones may have a lot less insulation, you know you get what you pay for.

To try an minimise temp loss, you could place some insulation above the mash.

The amount of water would have had no effect on temp loss. But opening the esky can and also if the temperature in the mash was uneven you may have miscalculated the temp loss.

Before your next batch why not do a couple of experiments and add only water at say 70c to the esky replace the lid and don't touch for an hour then check the temp, if it drops more than 1-2c then you'll need to insulate the esky. Keep doing these trials with more insulation until you minimise the temp loss.

Things you could use as insulation may include foam camping mat, polystyrene sheeting, silver windscreen sun screens, towels, etc..

AC

[DarkFaerytale]

i find i get temperature loss if i don't heat up my tun befor mashing, i use a willow 55L esky and add 2L of boiling water to it for 10 mins then run that through the pipe work, not only will it warm up your tun but it'll clean out your manifold/false bottom and the rest of your pipes

also do as AC says and make sure you have enough insulation, a peice of foam to fit your esky to sit ontop of the mash is great as most esky's don't have much/any insulation in the lid and then cover the closed esky with anything you can find (towels, old doona's ect)

-Phill

[chris.]

i find i get temperature loss if i don't heat up my tun befor mashing, i use a willow 55L esky and add 2L of boiling water to it for 10 mins then run that through the pipe work, not only will it warm up your tun but it'll clean out your manifold/false bottom and the rest of your pipes

I agree. I preheat my tun in the same manner & generally find that the temperature only drops a degree or 2 max.

[lethaldog]

Me two, i did a couple without preheating and although the temp loss wasnt that extreme it was deffinately better when i preheated, also the temp of the grains you are using will effect it to ( keeping in the fridge for example)

[Swifty]

I did pre-heat the tun. I haven't before but did this time. I reckon the insulation in the lid might be the problem, going to do a test this weekend and see. I can't really insulate underneath the lid though as sometime the tun is filled up too near to the top so might have to use towels or the thermo mat on the outside. Will test and see how I go. What about drilling a hole in the lid and filling it with something like the tyre foam stuff???

[DarkFaerytale]

What about drilling a hole in the lid and filling it with something like the tyre foam stuff???

this is another option, i think other people have used the selleys foaming no gap stuff, i'll have a look and find out

-Phill

[Swifty]

Thanks Phil, I'll try and stop and check it out tonight. Would look alot neater that way.

[DarkFaerytale]

couldn't find the thread but i'v read about it more than once, do a search on ahb and i'm sure you'll eventually find something about adding insulation the lid

-Phill

[Swifty]

Will do, I reckon you'd have to be able to do it though.

Thanks

[DarkFaerytale]

i'm positive you can

just be carefull that the product you use can handle upto 80 degrees, is alright around food and is able to get wet

oh yeah and be carefull when adding it, to much might split your lid!

[Swifty]

No problems with the lid, I've already got a spare esky exactly the same sitting under the house. When drilling the hole for the manifold bung I went through the base so any liquid would seep into the wall of the esky. So consequently I have a spare lid. Lucky it was only $20

[blandy]

After 30 min's though it had dropped to 63 degree's so I added 1.5L of boiling water and stirred only to find the temperature was still 63 degree's

"In this household we obey the laws of thermodynamics!" - Homer Simpson

---

Just a point not brought up yet: how are you measuring temp? My glass thermometer has a line you have to match with the water level. If you stick it in too high the themometer liquid expands too much and the reading is too high, don't stick it in far enough and it's too low.

I find it hard to believe that you've added 1.5L of 100*C water to what I'm assuming is about 10L of water/grain mix. Ignoring heat loss to surrounds, this should have resulted in a 4*C rise after good stirring. Even with heat loss, you should have registered some sort of temp rise.

[Swifty]

I use a mercury thermometer, I always make sure I stir well. I find it hard to believe too but it happens and I don't know why. The thermometer is a glass tube about 250mm long with mercury in it, I figure it should be accuracte.

[SpillsMostOfIt]

I use a mercury thermometer, I always make sure I stir well. I find it hard to believe too but it happens and I don't know why. The thermometer is a glass tube about 250mm long with mercury in it, I figure it should be accuracte.

Well, there's your problem. Buy yourself an earth thermometer.

[lethaldog]

I use a digital thermo
$12 from craftbrewer and one of the best things i have bought

[SpillsMostOfIt]

I use a digital thermo
$12 from craftbrewer and one of the best things i have bought

I own one myself. I keep thinking that there must be better things around, but when I look into it further, I realise that you can't get better value. Kill it and you've lost $12. I've calibrated it against everything I can get my hands on and it's surprisingly good.

[Dogger Dan]

I use a dairy thermometer and a digital meat thermometer.

Pre heat the esky, careful with the foam, it can warp your fermentor walls when it expends from heat. this can cause the walls to split (experience talking).

That is an amazing temp drop, if it continues get a new esky.

Dogger

[Ross]

get yourself a handheld immersion heater - takes all the stress out of getting your mash temp correct. Adding hot/cold water to adjust temp can be a nightmare. I now deliberately aim for a slightly cool mash temp, mix, leave 10 mins & then use the immersion (+1c/min) to hit the temp spot on.

cheers Ross

[Trough Lolly]

Yep, ditto here re the immersion element. Very handy when you use a 10 Gallon rubbermaid plastic cylindrical cooler that doesn't enjoy having a nasa burner under it!!

Cheers,
TL