Mash Tun size question is 20G too big for 5G

[Bohern]

I have done a search but have not found a thread that fits my circumstance, my apologies if I overlooked.

Here is details

I am ready to pull the trigger on a 3V herms system. I have priced out 20 gallon vessels going all electric with recirc of course.

Can I mash a small beer in this tun or is it too big? Will the grain bed be too thin?

It is a Spike 20G tun if that matters.

Thanks for your help!

 

[day_trippr]

I suspect a herms configuration makes the bed depth almost moot wrt extract efficiency and wort clarity.
If not fly sparging I'd just be sure to account for the plumbing losses when figuring strike and sparge volumes...

Cheers!

 

[Bohern]

I suspect a herms configuration makes the bed depth almost moot wrt extract efficiency and wort clarity.
If not fly sparging I'd just be sure to account for the plumbing losses when figuring strike and sparge volumes...

Cheers!

TY sir!

 

[govner1]

What volume do you normally brew?
Do you do any or a lot of high gravity beers?
Are you planning on making 10g batches routinely in the future?

 

[Bohern]

What volume do you normally brew?
Do you do any or a lot of high gravity beers?
Are you planning on making 10g batches routinely in the future?

5 and 10 gallon batches for 5% and 6% type brews and 5 gallon batches for the 9% above for right now.

 

[Gnomebrewer]

Spike 20gallon kettles are 17.7" wide. That's 45cm.
That makes the area of the base 3.14 x 0.25 x 45^2 = 1587cm2.
At 80% efficiency, a 1.048 beer uses about 8lbs of grain, which will use about 2.5 gallons of water, with a mash volume of about 3 gallons. I work in metric so that's about 12L or 12000mL or 12000cm3.
Therefore the depth of the mash will be about 12000cm3/1587cm2 = 7 to 8cm (about 3").

The short summary: a 1.048 beer in a 20gallon kettle will have a grain bed about 3 inches deep. I would expect that to be too shallow to work properly.

 

[govner1]

You might find some deals here-
https://spikebrewing.com/collections/v3-kettles?ref=3

 

[Vale71]

With such a thin grain bed you're almost sure to get channelling or at least have poor filtration leading to cloudy wort, which is a pity since exceptional wort clarity into the BK is one of the advantages of recirculation.

 

[Bohern]

With such a thin grain bed you're almost sure to get channelling or at least have poor filtration leading to cloudy wort, which is a pity since exceptional wort clarity into the BK is one of the advantages of recirculation.

That was exactly my thought as well. There was a miscommunication so all 20 gallon kettles were priced. I actually wanted it to be a 20BK, 15MLT and HLT.

Anyways it has all been worked out and I am getting 15’s for the two.

 

[Gnomebrewer]

That was exactly my thought as well. There was a miscommunication so all 20 gallon kettles were priced. I actually wanted it to be a 20BK, 15MLT and HLT.

Anyways it has all been worked out and I am getting 15’s for the two.

A 15 gallon MT will still be big for 5 gallon batches at normal gravity. For the beers you're talking about brewing, 10 gallons would be better. For 5 and 6% type beers, the ideal mash tun size is roughly the size of the finished batch.

 

[Bohern]

A 15 gallon MT will still be big for 5 gallon batches at normal gravity. For the beers you're talking about brewing, 10 gallons would be better. For 5 and 6% type beers, the ideal mash tun size is roughly the size of the finished batch.

What issues do you think I will need to watch out for? Or changes to make?

 

[Gnomebrewer]

A 5 gallon batch of 5 to 6% beer will have a mash volume around 3 to 4 gallons (assuming normal mash thickness). In a 15 gallon kettle that means about three quarters of the mash tun is empty. That means a big air space and surface area for heat to be lost and a shallow bed that is easily disturbed unless wort and sparge water is returned really gently. I use a keg with the top cut off as a mash tun - it's about 11 gallons - and find that it's workable but not ideal with lower gravity 5 gallon batches.

A 10 gallon batch of 1.060 beer (roughly 6%abv) has a mash volume about 8 to 9 gallons, so still fits comfortably in a 10 gallon mash tun.

So, if your plan is 5 to 10 gallon batches at 5 to 6% abv and 5 gallon batches to 9% abv, a 10 gallon mash tun will be more suitable.

 

[Bohern]

Well since it has been purchased I will need to figure it out.

Edit: That may even mean finding a different way to do the 5g batch.

 

[bracconiere]

Well since it has been purchased I will need to figure it out.

EASY! Drink more beer! lol (for the vitamins )

 

[Bohern]

Doing that right now, I mean taking my vitamins....yes, vitamins

 

[Bohern]

A 5 gallon batch of 5 to 6% beer will have a mash volume around 3 to 4 gallons (assuming normal mash thickness). In a 15 gallon kettle that means about three quarters of the mash tun is empty. That means a big air space and surface area for heat to be lost and a shallow bed that is easily disturbed unless wort and sparge water is returned really gently. I use a keg with the top cut off as a mash tun - it's about 11 gallons - and find that it's workable but not ideal with lower gravity 5 gallon batches.

A 10 gallon batch of 1.060 beer (roughly 6%abv) has a mash volume about 8 to 9 gallons, so still fits comfortably in a 10 gallon mash tun.

So, if your plan is 5 to 10 gallon batches at 5 to 6% abv and 5 gallon batches to 9% abv, a 10 gallon mash tun will be more suitable.

My main goal was to find the best compromise to do 5 and 10 gallon batches. As well as big ABV 5 gallon batches too.

 

[etk29321]

I successfully mashed a 3 gallon batch last Sunday in a 20 gallon mash tun. Hit my numbers and all went well. My system is a herms. I did no sparge and have ~1.25 gal in plumbing, so mash thickness was within a decent range. I don’t think I could be successful doing anything smaller.

Of course this was not a planned brew — I was out of dme and just needed enough wort for a starter for this weekend’s brew and no way to get more in time.

 

[Bohern]

mine will be a herms as well 15/15/20

 

[Bohern]

This bad boy is on its way.