Partial mash for larger batches

[Pehlman17]

I was wondering if anyone uses the technique of making a partial mash beer as a means to increase batch size due to grain capacity constraints. I suppose this is quite similar to what many do in order to make high gravity beers without making a smaller batch.
I brew on a 6.5 gallon Anvil Foundry and have been feeling like 2.5-3gal batches are just a hair too small. For as often as I’m able to brew around my work schedule, 2.5 gallons just doesn’t quite last long enough. I was hoping to shoot for around 4 gallons, but instead of having to get a whole new system, I thought maybe I could mash like I’m making 3 gallons and then top up with more water and some DME. Ultimately the DME would likely only make up at most 1/3 of my total fermentables depending on the beer. I’m pretty sure I could boil 4.5 gallons in the Anvil 6.5 without any issues.
Anybody else doing something similar or have any additional suggestions/recommendations?

 

[RM-MN]

I don't see any reason it wouldn't work and I'm not positive that you need to boil 4.5 gallons either. The boil does two things, it drives off DMS and isomerizes the hop oils for bittering. Your partial mash might need the boil for the DMS but the hop oils would still isomerize down to about 170F so that if you couldn't bring the full volume to a boil you would still get bittering. DME should have had the DMS boiled off in its formation so adding it later shouldn't matter.

I'd continue mashing as you would for a 2 1/2 gallon batch but with more hops for bittering, then add the extra water and DME to get the volume you want.

 

[Martys1]

I brew with an AF6.5 and I like to push the limits. I wanted to brew smaller batches but I would have to brew more often. I had a few 5 gallon kits that I divided in half, fermented in 2 carboys then blended together in the corny. So I’m trying to fill up the AF6.5 to the top.Since it was winter I brewed up some lagers. I was using 7# Pilsner 1# Munich and 4 oz carapils. I start with 4.5 gallons of hot water, mash in the grains , use the pump. Stir and raise the grain basket , mash out at 170 for 10, recirculate over the grains till clear, then I sparge with a gal of170, add hops boil, in the last 10 min I add 1/2 lb of fame and top up the rest of the way. I think I got a little more than 6 gal in the carboy. The wirloc keeps it from boiling over . I also got a bunch of inspiration from a brewer "Hops and Gnarley”, he does great stuff with an AF 6.5

 

[Pehlman17]

That's really cool to see. Thanks for the pictures! It looks like the larger boil volume shouldn't be an issue. I suppose I could always add an anti-foaming agent as insurance.

 

[Kharnynb]

I've been brewing in a 30 liter (so bit over 6.5 g) "tea-urn" style kettle for years and mostly do 20-22 liter batches, so over 5 gallons, just fill it to near the brim and stir when it comes to initial boil, keep a plantsprayer with water nearby to reduce any excess foam.

after mashing just run whatever extra water you need through the hanging bag to "sparge" it for some extra sugars.

edit: to reduce the confusion, step by step:
-for mash, have the full grain amount needed for a 5 gallon batch with as much water as will possibly fit in the kettle and mash.
-lift the grainbag to drain and add whatever amount of water needed on top of the bag "coffeefilter" style to get the most sugars out of your bag.
-boil as normal, there really shouldn't be more liquid than about 6 gallons if you consider about 15% boil-off to get 5 gallons

 

[Martys1]

Stupid spell correct, 1/2 pound of DME.

 

[Martys1]

I was wondering if anyone uses the technique of making a partial mash beer as a means to increase batch size due to grain capacity constraints. I suppose this is quite similar to what many do in order to make high gravity beers without making a smaller batch.
I brew on a 6.5 gallon Anvil Foundry and have been feeling like 2.5-3gal batches are just a hair too small. For as often as I’m able to brew around my work schedule, 2.5 gallons just doesn’t quite last long enough. I was hoping to shoot for around 4 gallons, but instead of having to get a whole new system, I thought maybe I could mash like I’m making 3 gallons and then top up with more water and some DME. Ultimately the DME would likely only make up at most 1/3 of my total fermentables depending on the beer. I’m pretty sure I could boil 4.5 gallons in the Anvil 6.5 without any issues.
Anybody else doing something similar or have any additional suggestions/recommendations?

I have an AF 6.5 also , I’ve brewed about 15 batches. I had a kit that had 11# of grain so I split that, but then I started pushing the limits, I did one batch that was 9+ lb grain.So now I brew using 7.5-8.5 # grain, I sparge w 1.5 gal of 170 water to bring the wort up to 51/2 gallons then boil w whirlfloc.
Hops and gnarly guy Dan did one that was 6 gal on you tube,it was right up to the top, but I wouldn’t turn my back on it