Friday, July 8, 2011

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!

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