Home Made Cool Box Mash Tun - Extra Insulation

I am getting ready to brew again, just waiting on some more grains arriving and so in the meantime I've been trying to address some of the problems I discovered during my first all grain brewday.

Firstly, my homemade, cool box mash tun lost around 6 degrees during the 60 minute mash and the mash temp was only just at the optimum temp for mashing (65c ish). The recipes in Graham Wheelers superb Brew Your Own British Real Ale (Camra) call for a mash time of 90 minutes so the temp loss will be an even bigger issue this time around.

Luckily I found a few slabs of 30mm polyurethane foam in the barn and set about building a tight fitting box around my cool box Mash Tun as well as a tight fitting lid with an additional thickness of foam inside.

The box was relatively easy to construct and is held together with some long screws. I made the lid so that it sites over the top of the box which also means that around 30mm of the sides around the top have a double thickness of foam too.

I haven't tested it yet as I've only just come in from finishing it but I think this additional insulation around the mash tun will make a great deal of difference, especially the 60mm total thickness in the lid (where most of the heat is reportedly lost).

PU Foam Insulation Box for my Home Made, Cool Box Mash Tun

EDIT: Well bollox! After all that it's only made half a degree C difference over 90 minutes. Started test with water at 65C. After 1 hour it was 61C and after 90 minutes it was 59.5 C - FFFUUUUUUUUUUUU

EDIT TO EDIT: Ignore the above, it seems testing a mash tun with hot water only gives less than favourable results. The grain in there also adds to the heat retention. This was proved in my subsequent brews, brew 2 All Grain HomeBrew Courage Directors and brew 3 All Grain HomeBrew Irish Stout when I lost just 1C  on brewday 2 and there was no measurable drop in temp on brew 3 :)

Hop strainer and mash tun filter changes...

With regard to the filter systems I built into first my mash tun and then my dual purpose boiler/copper I have had some great feedback from a couple of fellow brewers on Jim's Beer Kit forum.

Whereas I had drilled holes all the way around the piping, I would have been better just to drill the lower sides and bottom of the pipework.

The slotted filter in the mash tun isn't such a problem as all I need to do with that is simply turn the pipework over - another reason I chose not to permanently fix all the parts together just yet.

This isn't so much a case of the filtration not working but the dead space or rather the amount of liquid that would be left behind after draining and in effect, wasted. Less dead space = more beer at the end of the day.

Sparging System for Home Made Mash Tun

Spray bar for sparging the drained, mashed grist

As I am currently using a rectangular mash tun I decided against a rotating spray bar due to the smaller area of the width in ratio to the length of the mash tun. I would be stuck with a rotating arm that didn't spray hot liquor (water) over the drained, mashed grist (malted barley) at either end of the mash tun.

So, instead for starters I have chosen to build a static spray bar, albeit one that hopefully covers most of the surface area of the mashed grist.

The connector on the top will have a pipe from the aluminium boiler fixed on and hot water will be allowed to slowly trickle onto the drained grist, sparging it. The drain tap will be open from the start of the sparging process and the sparged liquid (I really do need to remember the proper terms) will flow into the previously drained wort.

Once sparged the mash tun has finished it's job. The liquid wort plus sparged liquid will then be added to the empty boiler and brought back to the boil ready for the addition of hops and any adjuncts (other flavour ingredients eg rice) required in the recipe.

Just a quicky post really, the spray bar is all 14mm copper pipe that has been drilled every 40mm, I may drill additional holes between the current ones if need be. I have purposely angled the spray bar stages downwards with a total drop from the water entry point to the end of the bar of about 40mm. this may or may not help the sparging liquor flow better and reach the last few holes.

Home made mash tun with sparging system and brewing boiler/copper for my first foray into full grain brewing

Building My First Mash Tun

10th July - I have amended some details. See this post re grist filter & hop strainer

Components for my first, full grain Home Brewing Mash Tun

What is Mashing and what is a Mash Tun?
Extract about Mashing Malted Grains from Wikipedia:

Mashing is the process of combining a mix of milled grain (typically malted barley with supplementary grains such as corn, sorghum, rye, rice or wheat), known as the "grist" or "grain bill", and water, known as "liquor", and heating this mixture. Mashing allows the enzymes in the malt to break down the starch in the grain into sugars, typically maltose to create a malty liquid called wort. There are two main methods - infusion mashing, in which the grains are heated in one vessel; and decoction mashing, in which a proportion of the grains are boiled and then returned to the mash, raising the temperature.[2] Mashing involves pauses at certain temperatures (notably 45 °C, 62 °C and 73 °C), and takes place in a "mash tun" - an insulated brewing vessel with a false bottom. The end product of mashing is called a "mash".

For my first mash tun I was going to create a false bottom using a perforated, stainless steel plate fitted snugly into the bottom of my insulated container (a Thermos cool box) leaving sufficient space below for the drain and valve that allows the liquid wort to be drawn off, leaving the mashed grist behind, ready for sparging. Sparging comes after the initial mash and is basically slowly pouring hot water over the drained grist to extract further loveliness into the wort... more on this at a later date.

However, stainless steel is not cheap and the insulated container has curved sides and ends that would making cutting (or having cut) a sheet quite aukward. Instead I opted to make a filter using everyday, copper plumbing fittings and pipe, slotted to allow the wort to pass through and onto the outlet drain and tap whilst retaining the mashed grist.

Also, to keep things initially, "simple" I have not fitted a heating element. Instead I shall add water boiled in a separate 34l stock pan to the grist in my mash tun.

So began my first venture, fully expecting a series of FFFFFFUUUUUUUUU rage inducing balls ups as is normal in my D.I.Y

My first task was to drill a 20mm hole through the insulated wall of my container. Through will be pushed a length of threaded, brass pipe with a plastic washer sealed locking nut on the inside and standard rubber washer on the outside of the box. The valve will be fitted to the outside and the copper filtration system fitted to the inside.

20mm hole drilled into cool box wall.

I inserted the threaded brass pipe - which was a nice, tight fit - through the hole and secured it on the inside and outside with 2 locking nuts and washers to seal it all up.

Brass pipe secured in place and ready to take the mashed grain filter

Rather than show all of the stages, making the internal grain/grist/mash filter I'll just show the finished component. It's composed of:

• 18mm Copper pipe - approx. 500mm
• 4x 18mm 90deg elbows
• 1x 18mm T
• 18mm coupling (not sure what it's called, tank union possibly) with a female, threaded end that tightens on to the projecting stub of the threaded brass pipe.

I cut slots roughly 10mm apart and through about half the diameter of the copper pipe and push fitted it all together. I have not soldered any of it. I'll see how it behaves during the first brew and if it comes apart will consider probably joining it all together with a series of good, centre punch wallops on the ends of the fittings. I hope it's ok as it is as I'm sure it will be easier to clean out after use if it's able to be broken apart.

Home made mash filter ready to connect into my mash tun

Once I had it all cleaned up and connected, I fitted the valve onto the outside and gave it a good tighten. now came the important part, would it leak? I filled the mash tun with cold water and waited...

Mash tun filled with water to test for leaks... seems ok so far.

There was a slight drip from the valve side of things, FFFFFUUUUUUUUU- so I fitted and internal washer, wrapped some PTFE tape around the thread (I should have known - after a lot of plumbing during the refurbishment of our house in France, that everything you buy for plumbing these days leaks - and done this in the first place) and re-fitted the valve. After a further water test there was no sign of any leak :)

My home made, full grain home brewing mash tun (version 1)

I think I will still look at creating a mash tun using a false bottom but I'm sure this will get me started with my first few brews. Now it's just a case of sourcing a good supplier that won't take my eyes out with postage costs.

I've joined a couple of good home brewing forums, Jim's Beer Kit and a French one, Brassage Amateur both of which I have found invaluable and a pleasant bunch of members to boot!