Mash temperature loss

[cnelsonplumber]

I have been dabbling around with my home made mash tun and carried out a series of trials to try and reduce temperature loss over the 90 min.

The original loss from 68 degrees C was 7.4 C over the 90 min

Most of the heat loss was through the top of the box so I invested in a well known DIY centres expanding foam which I have to be honest was not a great success as it made very little difference.

I have wrapped the former cold box in bubble wrap and a space blanket backed by a foam protective layer and manager to get the loss down to 5.8 degrees over 90 mins. I think I could reduce this a little further by pre heating the tun to say around 75 degrees for 30 minutes but
is the drop going to adversely affect extracxtion of the sugars from the malt.

This will be my second AG as the first one went down the drain, so I am keen to get it closer to correct this time!

 

[Runwell-Steve]

Thats a big temperature loss.

Are you pre heating the Mash Tun fully before adding the ingredients. Put a couple of kettles full of boiling water in it and leave it sealed up while your Strike Water is coming up to temperature.

The kind of temperature loss you are talking about it sounds as if you aren't. You really do need need to pre heat your tun, or add the strike water hotter to compensate.

How are you checking your temperature loss over the 90 minutes are you checking with just water, A mash will hold it's temperature better than just water.

The more contents you have in the Tun the better it will retain its temperature. 25L will hold its temp much better than 10L.

 

[micmacmoc]

I put a sleeping bag in the airing cupboard the day before, wrap the tun in this and its usually a matter of 0.5C if that heat loss, worth a try!

 

[BigYin]

That's a BIG loss - I did my first flirtation with the overnight mash method last night.. just over 5kg of grain, 15 litres of water (sorry, liquor :lol: ), in my home made mash tun, and put a folded towel on the lid for extra insulation, 6 hours later it had only lost 5.8c :clap: :clap: :clap:

 

[dennisking]

A camping mat, cost a fiver, you can attach permanently to the outside of the tun, then pre-heating and wrapping, I wrap in a hot water tank jacket and get no loss.

 

[BigYin]

I've used 3 layers of Homebase ThermaWrap around an ordinary plastic fermenter, all neatly held in place with duct tape. Negligible losses at 90 minutes (around 0.1 to 0.2 c) :drink:

 

[NegFerret]

I have the same mash tun and had significant heat losses over 90 mins through the top.

Now I cover the top with a layer of bubble wrap, then a layer of foil (shiney side facing towards the tun) and finally a thick blanket folded over itself a few times. I now get 1 degree of loss over 90 mins.

Hope this helps.

 

[cnelsonplumber]

Just finished a few mods to the mash tun comprising extra layer of bubble wrap and laminate floor insulation with the gold side facing in and a couple of blankets over the top. Maximum pre-heat with near boiling water for 30 mins prior to strike at 68.2 degrees. Will know in 90 minutes if it is effective.

 

[cnelsonplumber]

Bad news - Still lost 4.6 degrees. Even with a thick wool blanket over the top of all the other insulation.

Also developed a small leak due to a crack in the corner of the inner shell - Back to the drawing board

 

[dennisking]

Don`t think you will lose as much when you have grain and water rather than just water.

 

[cnelsonplumber]

Thanks DK but I think it's time to knock this mash tun on the head.

I have an Electrum Heated mash tun but only use it for boiling up water for my wine as the temperature control is not great.

Might give that a go but use a nylon bag to save the malt sticking to the element when the heat cuts in. I hav'nt read much about this technique on the forum which leads me to think it may not be the best way to go about extracting the sugars.

 

[Muddy Funker]

A few people have said this now, if it's just water you're testing with then you will be losing a fair few degrees over the 90 mins.

When the grain is added these will retain the heat massively. The fair few degrees you were losing before should be more like points of a degree after.

 

[cnelsonplumber]

That's encouraging. I was beginning to think that the MT was a dead loss.

I hope to have a go at AG next Mon as stocks of my kit beers are running low.

 

[dennisking]

That's encouraging. I was beginning to think that the MT was a dead loss.

I hope to have a go at AG next Mon as stocks of my kit beers are running low.

Think you will only know by trying

 

[Mr_Zee]

I was getting similar losses through my converted Igloo 10 gal thermo box.

A reason that has not been mentioned is the bottom getting cold. I soon realised that having the MT on a stool or shelf allowed the bottom of the MT to cool very quickly.

I now place it on the floor of my brewery (floor covered with artifical turf). I am only experiencing 2 degree loses over 90 mins. All I do is cover it with a couple of coats.

I put the 2 degree loses down to having quite alot of unfilled space inside the MT (bigger brews required :party: ).

Hope it helps.

 

[cnelsonplumber]

All that worry for nothing.

I used my mash tun in anger for the first time yesterday. I had temperature losses of around 4 degrees c with water, but when I used grain at 2.5 Ltr/Kg then the loss was less than 0.5 C around the outside of the mash and nil at the centre.

It has developed a small leak due to the heat which I will repair with epoxy resin around the outside of the inner skin. Hopefully it will keep me going until santa brings me a shiny equivalent. Just in case Santa is on line one of these would be nice please.