Grain amount limit for 40L Urn

[Major Arcana]

G'day Fellas,

I know this question has been addressed somewhere before by Bribie G but cant remember where, what i would like to know is "What would be the maximum amount KG wise for my 40L crown urn? I start all my batches with 31L and am using approx 5-5.5kg of grain etc.
Has anybody used 7kg of grain before? A lot of the recipes i want to make are around 6-6.5%abv and as i mentioned have a total grain bill of approximiteLY 7KG.
I should also mention i am transferring between 20-23L into the cube.

Any advice would be greatly appreciated.

Cheers,

Dan

 

[Dan Pratt]

Here is a link to use that has a section for - Can I Mash it? enter the kg of malt and the water to grain ratio, so 31lts is 4.42lt per kg and it tells you the answer.

http://www.rackers.org/calcs.shtml

You could look to reduce the start volume and sparge with 3-5lts to get that volume back before the boil aswell to make be sure.

And another thing to mention is, if your making and IPA that = Hops and hops take up wort. You will be left with trub when you tansfer to the FV and you will need to calculate the grams of hops times 12mls per gram to know what to add to your known trub loss. This way your target volume for the batch will be closer or you may just get a bunch of trub/hops into the FV which wont hurt either.

put it simple, 100g of hops will = 1.2lts of additional loss to trub.

Hope that makes sense

 

[indica86]

7.65kg is the most I have used.
Highest ABV is over 9%

 

[Markbeer]

I have used 10 to 11kg. It's a bitch to work with. Then sparge to get better efficiency and preboil volume.

 

[oglennyboy]

I found by doing BIAB and leaving out say 5-6 litres as a sparge at the end of the mash I'm comfortably pushing 6.5-7.5kg for 22-23 litres into the fermenter. Typically OG 1.062-1.070. I can do that without holding water back, but it's right at the lip, so it's hard to mash.
Had a bit of trial & error with my mill settings, and with a good pumping of the mash for a few minutes at the start & a couple times throughout find I'm always around 86-89% efficiency for wort into the start & end end of the boil. Using a hop spider means there's about 3.5-4 litres trub, and I'm not super fussy about keeping cold break out of the fermenter. The urn is a 44 litre job.
Last month I pushed 12.5kg through in one hit to end up with 19 litres in the fermenter at SG 1.102, but that was a massive pain in the arse and ended up with a bag I couldn't even lift! Had to scoop grain into a colander & sparge & press & carry on like a pork chop. With an all day mash, 2+ hour boil and all the rest, it was a 9 hour day.
But it can be done
cheers!

 

[anthonyUK]

I made a Yeti RIS clone late last year using 9kg of grain.
My efficiency dropped below 60% and I could've done with more sparging as the runnings were still 1.040.
It worked out well but as mentioned it can be a bitch to handle that amount of wet grain.

 

[Alex.Tas]

Within reason you can use as much as you want. Don't be scared to push the limits. I made a RIS on my crown the other day, my first foray into high gravity brewing and I managed to get 21l final bottling volume with an OG of 1.096. Just hold back your initial strike volume and use it to sparge. Sparge multiple times in lower batches to increase the effectiveness of your sparge.
ie two sparges of six liters would be better than one of twelve.
A skyhook helps, along with a large sparging bucket. I use a 20l pail for standard brews but this certainly wouldn't have cut it for the RIS. Be prepared for some mess too.

 

[stux]

Without a sparge, your efficiency will eventually drop below 50%. the actual limit as more grain will just result in less beer!

One or two dunk sparges in 5-10L in a 20L pot will help get through that efficiency barrier

Do a dunk sparge by dropping the entire drained grain bag into another pot of 80C water (it'll cool), reopen the bag, and rewet/agitate the grain. I leave it fir 10 minutes, then re-raise the bag and let drain.

Bit like re biabing the grains. A spare skyhook helps.

Add as much of the sparge rubbings as you can to your urn and then start boiling your sparge pot. Add the remainder of the runnings to your main boil as you evaporate off additional liquid

 

[Bribie G]

Came in late here.

During the summer, as I only have one fermenting fridge, I make a series of keg fillers using my 60L fermenter to do a 42L batch that fills two kegs plus a sampler or two.
I either do two separate mashes or:

Do one only mash using around 7kg of grain and give the voile a good squeeze.
No chill in 3 ten litre cubes.
Add a tin of Coopers - something really bland like a Cerveza or Canadian.
top up to 42L in the fermenter, add some dex if the efficiency has been a bit low.

This gives me a light flavoured lager-ale quaffer. It could even work with APAs I suppose with a few more crystals and hops.


This is what the urn looks like with a 7kg mash and what it looks like after the boil.





Efficiency isn't massive, about 75%. I could improve that by doing a sparge but the reason I'm doing it is to avoid too much dicking around in the first place, so I'm quite happy to take a small hit.

The only time I've used a really big grain bill for a RIS, I did a massive sparge and a long, long boil. I've lost the recipe, I believe it was around 8.5kg.

 

[lael]

I made a Yeti RIS clone late last year using 9kg of grain.
My efficiency dropped below 60% and I could've done with more sparging as the runnings were still 1.040.
It worked out well but as mentioned it can be a bitch to handle that amount of wet grain.

Off topic:
How did the yeti ris turn out?

 

[Bribie G]

RdeV, I see you liked my post... the batch of American wheat I brought up with me to SEQ for Xmas was a partial as described above.