Understanding Grain And Water Volume

[bcp]

In planning for beers with a higher grain bill, it's easy to work out when you have more water than pot. I could also work out the amount of space the grain takes up dry - but it absorbs water, so that changes it.

So what i'm not sure about is how many kg of grain added to the water starts to mean i'm out of space.
1. There must be a formula for calculating the volume of the grain itself? (xkg of grain + xlitres of water = 40 litres space). or (xk grain = xlitres of grain).

2. Or for the more immediate and simple answer, i have a birko 40litre urn & BIAB. What's the biggest grain bill i should attempt for a 23 litre batch normal BIAB style? 8kg? 10kg?

3. Presumably after that i could potentially hold some water in reserve to 'sparge' the bag, thus increasing the effective volume = or brew at a higher gravity and add water later. = or put some of the grain/water in the kitchen 10 litre pot and add it to the boil later?

I've got a larger grain bill with my next brew, and was rather surprised with the volume of the first smaller one!

 

[raven19]

I can confirm a 25kg sack of uncrushed grain will just fit into a 48L plastic tub.

So allowing 2L per kg is a safe mark to start with.

(If I do big batches in my 50L esky I can just squeeze in 12 - 13 kg of grain with a thick mash and fly sparging. In saying that, the esky only holds around 40 - 45L before it leaks over the lid hinge).

Edit - higher gravity brewing will drop your efficiency slightly, but may still be a good option

 

[Phoney]

I brewed a 5.5kg grain bill the other day, and a 32.5L water start volume and that just fit into my Birko 40L. I reckon that was about maximum. I had to be careful when stirring the grains with the mash paddle so that it wouldnt spill over the edge.

I still could have made a higher gravity beer using more grain, if; I done a 60 min boil instead of a 90min and I aimed for 20/21L instead of 23L. But I think if I wanted to make a big beer with 8-10kg of grain (ie: Russian imperial stout or something similar) I would split the grain into two batches. I havent done this before so cant comment any further unfortunately...

BribieG may offer some good advice here

 

[crundle]

In my 40 litre Crown urn, I pretty much always use 30 litres of water to mash with, and then squeeze the bag to see how much water I have lost. I always aim to get back to at least 30 litres pre boil, so I will sparge the squeezed bag with enough boiled water to get me back to 30 litres preboil, with an expected efficiency of 75%.

This is for grain bills of under 5kg. If the grain bill is higher, I expect to get lower efficiency, so I will use more water to sparge with, bringing my pre boil volume up to 32 or 33 litres. A close eye needs to be kept on the boil for the first 30 minutes, but once it has settled down, I can hope to get around 75% efficiency in a larger grain bill if I have sparged with enough water. The flipside is a longer boil of course, so I may end up boiling for 2 hours, and start my 60 minute hop additions once the water level reaches 27 litres on my urn.

At the 27 litre mark, I know that I will end up with a cube full of wort with little left in the urn.

The largest grain bill I have used so far was 9kg for a Doppelbock, and I had to use a lot of water to sparge with, and consequently boil for about 2 hours to get a reasonable final gravity and an efficiency of about 68%. You can expect lower efficiency for a bigger grain bill, but may be able to offset that somewhat if you mill your own grain by milling it much finer than you could if you used a traditional 3 vessel setup (definite stuck sparge territory).

The best way to overcome the limit of a 40 litre urn is to use time to your advantage. You can sparge using a separate bucket and squeeze the bag to see how much good sugar is still coming out, and add the resulting liquid slowly over the course of the boil to avoid boil overs, but still give it enough time to get rid of any DMS precursors. The key is to not start your hop additions till the level reaches a certain point, as once you have put in the hops, you are then limited to a 60 minute boil to remove any excess liquid. After a number of brews, I have found 27 litres to be my mark to begin my hopping, knowing that after 60 minutes I will end up with a cube full of clear, good gravity wort.

cheers,

Crundle

 

[bcp]

That's all really helpful feedback. The recipe i have has a 7kg grain bill. With your doppelbock, did you actually check the gravity during the boil, or do you just shoot for the 27 litre mark? (Because checking during boil requires time to cool a bit - i stupidly melted my plastic test tube last time).

 

[crundle]

I didn't check the gravity during the boil, as I only have a hydrometer at this stage, and didn't want to melt the tube as others have done. For the Doppelbock, I used a lower efficiency figure in Beersmith to allow for getting a lower efficiency and it ended up about on target at 8.5 % (and I subsequently lost it to acetobacter in the secondary but that is another tale of woe).

If you are currently getting about 75% efficiency for a 5kg or less grain bill, maybe set your efficiency to 70% for a 7kg bill and see how you go.

I basically use the 27 litre mark as my start point by experience, knowing that in 60 minutes from there I will be able to fill a cube to the brim with wort of around the correct gravity with little waste left in the urn. My understanding is that the Birko has a better boil, so you should be able to set your hops to start at around 27 litres and end up with about 24 or so litres at the end of 60 minutes. The only issue with electric urns is that the boil is not able to be varied as with gas, so you can't make it evaporate quicker by turning up the dial, although I have an immersion element for that purpose if the situation is dire. But since I have gone from boiling for exactly 90 minutes each time to boiling till I hit 27 litres then starting my 60 minutes for hops, my starting gravities have been spot on each time.

It is a matter of getting to know your equipment, and it is different to each setup, but take notes of your starting volumes, grain bills and boil times, and you will hone in on your own setup's best settings in no time.

I am hoping to get a refractometer at some stage this year, and will then start to take samples to work out when to start my 60 minute hops schedule, but as I am doing it now seems to work very well, and is easily repeatable if you put some volume marks on your urn for reference. NOTE: I *think* I made my marks to the level when the water is cold, and as it expands by 4% when boiling, this may be an issue the first time you try boiling by volume instead of time, but after one brew you will learn what volume you will need to set it to.

cheers,

Crundle

 

[Phoney]

At the 27 litre mark, I know that I will end up with a cube full of wort with little left in the urn.

Slightly off topic, but:

Up until recently I had been pouring the entire contents of the urn into cube. For the last couple of brews ive whirpooled at the end of the boil, then let it sit for 20 mins, then poured into the cube. I was suprised at how much gunk (is this hot break or protein?) was sitting in the bottom of the urn! So from now on I now leave about the last 1 - 2L of wort - full of gunk - behind in the urn. I havent tasted the final result yet to compare but I can notice how much clearer the wort is already. This of course adds another 2L of water to my start volume...

Is it worth leaving out the gunk?

 

[crundle]

Some say yes, some say no.

I use a hop sock, so I don't have to worry about hops remaining in my cubes while they cool, adding to perceived bitterness (no flame war please). So for me, I will let the hot break into the cube if the cube has any room left, but not if I am over the cube volume. I haven't seen or tasted any effect of having the hot break in my fermenter from the cube, and there is a school of thought that it might provide some nutrients for the yeast during fermentation.

Having said that, I do crash chill my fermenter to make anything drop out of suspension, and use gelatine in my kegs, so I still get a nice clear beer, but IMO, there is no real difference, other than aesthetic.

If my end of boil volume is down a bit, I would rather not lose the extra liquid to maintain a nice clear wort, but if I am over my target volume, then I will leave the hot break behind.

EDIT: You will still end up with cold break in the cube anyway, so to me it doesn't matter much about clarity at that stage, as long as the final beer is clear. I am thinking now though, what are the real differences between hot break and cold break, are they made from the same type of matter, or are they different, like longer chain proteins in one and not the other?

cheers,

Crundle

 

[seemax]

The gunk is a mixture of trub (break) and hops. You can either leave it behind in the kettle using the whirlpool method or drain it all into your NC cube or fermentor and let it settle after fermentation.

You can also filter the last few litres of wort from your kettle using a hop sock or voile.

 

[DKS]

I've always been told and read, hot break is bad news. Do your best to leave it behind.




Yuk!
Daz