Mash tun - first test run - big problem :(

rivetcatcher

I have just finished my brewery and decided to go for a test run today using only water.

The plan was to follow the brew day step by step guide - without the grain etc just to get the feel for how the system works and spot any problems. My first brew will be the electric pale ale sessionable version. I have tweaked the brewery step buy step guide to fit the electric pale ale and my system.

Just a bit of background on my build. I am currently based in Thailand so getting all of the parts etc as recommended by Kal is almost impossible unless you are prepared to pay massive shipping and taxes - something I was not prepare to do. I did however have to import a few bits and pieces.

I decided to build my system using 25 gallon stainless stock pots that are easily available here. I installed sight glasses, weldless fittings etc. For the false bottom I imported a custom false bottom from Norcal brewing solutions - which was exactly to spec and in my opinion a great piece of kit. However, this is where I have overlooked a very important detail. When transferring the strike water from the HLT to the mash tun (approx 5.9 gallon) I found that the stand I have made for the mash tun to sit on is too high. This means that I have about 4 gallons under the false bottom and about 1.9 gallons above it. I can't lower the stand as when I built the pot the stand was specifically built to sit above the outlet for the valve and sight glass. Effectively there isn't going to be enough water above the false bottom to steep the grain.

Just for info the deadspace under the false bottom after draining the water out is 0.35 gallon.

Any ideas on how to get round this? Is it a big F*** up? Should I add extra strike water and decrease the sparge water?

Or.... do I have to re-make the Mash Tun?

Any help is appreciated.

Cheers

Rivet

PS. I also found another issue which was a broken quick disconnect without an o-ring seal. I highly recommend test running your brewery before diving in with grain.

**kal** · Posted: Sun Jul 16, 2017 1:00 pm Post subject:

Can you post some pics to get a better sense of what it looks like?

Kal

rivetcatcher · Posted: Sun Jul 16, 2017 2:48 pm Post subject:

Oooops... correction to above, meant to say that the stand for the false bottom to sit on is too high, can get some pics, how do I upload? Do I need to have photobucket?

**kal** · Posted: Sun Jul 16, 2017 3:43 pm Post subject:

You can link to photos elsewhere or just click 'go advanced' below and upload directly to our forum.

Kal

rivetcatcher · Posted: Mon Jul 17, 2017 2:17 am Post subject:

So here are the pics:

This shows my setup so far.

This shows mash tun with the false bottom installed. Dip tube and sight glass are underneath.

This shows the false bottom removed showing the dip tube, sight class connection and stand.

Cheers

Rivet

Mr Walleye · Joined: 23 Dec 2013 Posts: 71 Location: Ossining, NY

I'd want a little more water above the false bottom myself.

Any chance of lowering it a bit by modifying the stand and making a nice snug notch for where the dip tube comes in, and maybe the sight glass port?

McGruber · Joined: 12 Aug 2014 Posts: 237 Location: Idaho

I think so long as you mash in with the correct volume above the mash filter, you'll be just fine without modifying anything. If you have the correct grist : water ratio above the screen, then technically (from an enzyme perspective) it shouldn't matter how much liquid is below the mash screen.

That being said, the volume of water below your mash screen might cause some dilution of the gravity you might expect from your first runnings, but the total sugar extract you get from your grain is more directly tied to your mill and lauter efficiency (just like everyone elses set up). For example, you can only extract "X amount" of sugar from any grain profile. If you use more or less water to do it doesn't change how much sugar is available to extract. Therefore, you may find that you have to sparge less volume to hit your pre-boil numbers, and/ or you might have to boil longer than you expect to concentrate the sugars to hit the correct OG. However, I don't think so. I think you'll collect (for example:) 14 gallons in the boil kettle for a 12 gallon batch with a 2 gallon per hour boil off rate and one hour boil, and I think you'll hit the same numbers as someone with a smaller volume under the screen that sparged more to hit the same pre-boil volume (assuming same boil off rate).

I think you'll be fine. Try it a few times as is (but do keep the correct water : grist ratio above the screen. So if you have 4 gallons below and you're supposed to mash with 6 gallons then you'll need 10 gallons of strike water. If you don't have brewing software, get one and track your pre-boil gravity, boil off rate, post chilling OG and brewhouse efficiency. It'll probably take 3 - 5 brews of a *similar beer to identify a trend (*Don't make a lager, a pale, a wheat beer, a pumpkin beer and an imperial stout and expect similar efficiency numbers).

Just my opinion. I'm curious to see what everyone else has to say. Good luck!

rivetcatcher · Posted: Mon Jul 17, 2017 8:32 am Post subject:

Thanks for the replies.

**kal** · Posted: Mon Jul 17, 2017 12:56 pm Post subject:

I think you'll be fine. You may have some issues trying to make really small volumes of beer exactly the way you want as there'll be more water than you may want but I think it'll be ok. I also think the liquor to grist ratio does not have a huge effect on the beer (a more water grist is supposed to be more fermentable).

rivetcatcher · Posted: Mon Jul 17, 2017 1:38 pm Post subject:

The water under my mash screen is not all dead space, there is a lot of water under the screen however only 0.35 of it is actually dead space. My biggest concern is not getting all of the grain wet. Kal, what would you do to compensate if you had this issue?

**kal** · Posted: Mon Jul 17, 2017 3:03 pm Post subject:

We're having some terminology differences: The area under the false bottom that contains only water (not grain) is called dead space. So I'm not sure what you mean exactly when you mention '0.35 of dead space'.

All the grain should be wet as long as there's enough water in the mash tun.

The only difference on your setup is the 0.22 gallon value in my formula above. Use whatever amount of water you have under the false bottom instead. The amount in the hoses may be different too if your hose lengths are different/if your HERMS coil length is different.

Good luck!

Kal

McGruber · Joined: 12 Aug 2014 Posts: 237 Location: Idaho

**kal** · Posted: Mon Jul 17, 2017 8:27 pm Post subject:

Makes sense McGruber! Hopefully he won't have anything extreme enough to have dry grain.

Kal

rivetcatcher · Posted: Tue Jul 18, 2017 12:25 am Post subject:

McGruber · Joined: 12 Aug 2014 Posts: 237 Location: Idaho

sirmellor · Joined: 19 Feb 2013 Posts: 16

If I'm understanding this correctly could you find a container or object that will fit under the false bottom, not touching it, that would displace the water under the false bottom. For example it could be as simple as some clean smooth rocks, or a block of stainless steel, or what ever you have around the house.

Cheers, Richard.

rivetcatcher · Posted: Wed Jul 19, 2017 12:17 am Post subject:

blazinlow86 · Joined: 15 Jan 2017 Posts: 104 Location: vancouver bc

i have a similar norcal false bottom and had the same issue with deadspace however mine is 2 gallons below the bottom. i had issues trying to do a 6 gallon lager with a really light grain bill in my 20 gallon mash tun but with my normal 12 gallon batches it works great. i use 1.8 qts/lb for my water calculator and 82% eff ( i do a quick fly sparge).i also have a genaric 12 inch fb i can use for smaller test batches. with 25 gallon kettles your probably not going to be able to do small batches but 12+ gallons should work well

rivetcatcher · Posted: Fri Jul 21, 2017 12:58 pm Post subject: