Is bubble/foil insulation any good?

[nobby]

Pre-heating is the best way to keep your MT temp constant. Put about a gallon of boiling water in your MT for at least 30mins to an Hour before you Mash.

[Blackjack]

Oh yes, it does something. When there's a high heat flow from a boiler with no insulation the losses are so massive that even a little bit makes quite a difference. But not so much from a cooler MT thats already insulated though, there the difference would be much, much less noticable.

Cheers
kev

As an engineer I can endorse this comment 100%.
If you want to reduce losses from the hlt or the copper and use less electric etc. then this shiny bubble stuff is good and I have a roll waiting for installation with velcro fixings.

If the problem is the MT then it will have a negligible effect. As a very quick fix some months ago on a small MT I stood it on a sheet of 22mm celotex insulation and put a similar piece over the lid.

As a suggestion for something similar then buy a pack of 50mm extruded polystyrene insulation sheets. 4 or 5 per pack and approx 500mm X 1200mm. and make an outer tea cosy for the MT. Most glues will either dissolve the polystyrene or if water based will take literally weeks to dry out and set, so stick sheets of this together using WATER based EVO impact adhesive. ( Great for model railway scenery as well! ).

[jmc]

Hi

Thanks for all the replies and suggestions.

On recent mashes I've placed cool box on 4 layers of thermal insulation matting (the green stuff for walls & floors about 1cm thick). Then 4 layers of matting on top then wrap with 1 camping mat and cover in thermal (emergency) plastic foil blanket and strap up with luggage straps.

I always preheat with water about 82-84C for close & and wait for 10 mins then wait for water to reach strike temp (typically 72-74C) before adding grain & doughing in.

I agree the insulation in the lid is not brilliant (it feels warmish) after mashing. Its also not a really tight fit. I've undone hinges to both stop condensation running over insulation when I open coolbox and also to allow strapping to force lid down. Maybe a heavy weight would help as suggested.

It does have insulation in the lid though, as it can be seen in some small (1mm) holes at edge.
I assume these are there to allow foam to expand in the lid during manufacture. Lid does have 6 circular recesses (I dont see any reason for them). These look like they have no insulation so they are likely 'hot' spots.

I only do 5 gal batches, so I realise coolbox is a bit large for this and would offer better thermal efficiency with 10 gal batches.

I took Capped's advice

I dunno about that bubble foil stuff,but you could do far worse than that red lagging used for insulating hot water tanks. I've used it for years and it works brilliantly - even on a 'naked' FV used as a mashtun I never saw more than a 2C drop over 2 hours.. And it's dirt cheap and even comes with some plastic straps to secure it with!

Luckily they are on at the moment at only £3.98 at Wicks, so I got one prior to a mash Friday evening


Link to Wicks Cylinder Jacket Page

They unpack to form 4 separate sections that are a good fit for this size of coolbox.

Due to lack of time I had to do an overnight mash on Friday night and with just cylinder jacket sections and thermal matting underneath, temp went down from 66C to 50C in 10 hours 23:30 - 9:30.
This is 10C better than previous overnight mash, so it is better.

Thinking about it, when I unwrapped the cylinder jacket sections I got a waft of malty air so there must be an air leak of some sort. I'll add a weight next time to hold lid on better.

When I do a std 90min mash I'll post results.
Thanks again
ATB
John