Batch sparging - confused

[SZM]

On my first AG, I got in a pickle about volumes. I am using Graham Wheelers book and doing the sparging by batch sparging. I ended up with a fair amount less at the end of the boil than was aiming for (it was at the right OG which may suggest the loss had made up for my lack of efficiency earlier).

Anyway this time am doing a Ringwood Porter recipe aiming for 23 litres and with GW suggesting I need to treat 33.3 litres. I used Jims calculator and got a different result - see below

Enter Volume Required In Fermenter ie Brew Length 23L
Percentage Loss During Boil 15%:
Enter estimated loss to hops and trub 5 litres (ie matching 5kg of grain)
Total Grain Bill e.g. 5kg
Enter Dead Space in Mash Tun: 0.1L (guess)
Enter Water/Grain Ratio for the Mash in Liters, 2.5 L/kg
Wort Required for the Boil: 32.9 L
Made up from two equal quantities of: 16.5 liters of wort collected from the mash.
Total Quantity of Water Required For Batch #1:21.6 L
Mash Volume: 12.5L (this is the same as GW)
Top Up With: 9.1L
Water Required for Batch #2: 16.5 L

If anyone has time and inclination, I would really appreciate some guidance on whether i have done something wrong in the calculation. this would suggest 37 odd litres needs to be treated. Also, is all batch 2 added at the same time?

Thanks in advance
simon

[PureGuiness]

Enter estimated loss to hops and trub 5 litres (ie matching 5kg of grain)

This is probably too much. This does not relate to the grain but the amount lost to the hops and other trub in the boiler so it doesn't touch the grain. The losses to grain are already calculated when you enter the amount of grain in the mash.

Other than that everything looks reasonable.

[Scooby]

GW's instructions after sparging state;

'Top up the boiler with treated water to a volume as near to the final volume as can be achieved'

Then after cooling 'the wort is adjusted to the correct specific gravity by adding cold water'

When using the calculator the volumes are such that what you get in the fermemter is the final batch size.

PG is also correct in his point about losses, it's boiler losses you need to input there, the calculator automatically works out the losses to the grain.

So if you correct the losses to hops and trub to about 3l and check you tun for dead space (fill with water and drain then measure the water remaining in the tun) as 0.1l is extemely minimal and you'll find the calc's are quite accurate.

Make notes on your brewday so as you can implement a few tweeks on the next brew and get it spot on

[Northern Brewer]

Stop worrying - It's very easy. Scaling up my own methodology to reflect your 5kg

Mash 5kg with 13 litres at around 74C

After 90 minutes stir-in a further 9 litres @80C and drain.

Once that has pretty much drained stir-in a further 15 litres and drain.

You will collect around 33 litres in total.

The final litre or so will be fairly elusive, so get the boil under-way beforehand and add these dregs afterwards.

[crookedeyeboy]

Ive only got a small-ish mash tun so I tend to start running the wort out after the mash very slowly but then start adding the first lot of batch sparge water at the same time, trying to keep a head of water on top of the grain bed.
It seems to be working as I have just beenm pursuaded to keep doing this rather than swapping to fly sparging...with an efficiency at 82% im not about to fix something that isnt broken!!

[crookedeyeboy]

Nowt wrong with the quality either!! its just being drunk too quick!

[Parva]

Enter Dead Space in Mash Tun: 0.1L (guess)

You may also find that that is a very optimistic figure. Put some water into the mash tun and drain it off through the tap. When it stops tip the remaining water into a jug and measure and voilla, you have your dead space figure.

[OldSpeckledBadger]

My boiler's a bit on the small side - 27 litres filled to the brim. To give a bit of protection against boil-overs I started with a max volume of 22 litres. Once that was nicely settled on a rolling boil and the foam dissolved, I added a couple of litres of boiling water. At the end I collected about 18.5 litres but even after diluting to the full brew length I was significantly over the predicted SG with an efficiency of 82%. I think the idea that you need to collect significantly more wort than the brew length to get a decent efficiency is questionable.

[Northern Brewer]

If you already know how much wort you wish to collect, and your mash tun has spare capacity, then the following will get you into the right ball park...

Decide upon how much wort you wish to collect.
Halve that figure to determine the second top-up volume. Call this figure X
Grain absorbs approx approximately 1 litre per kg*
Calculate the total absorption figure, then add this to X to produce Y
Deduct your mash liquor volume from Y then call the answer Z
Commence you mash as normal then heat X + Z to 80C.
Once the mash is complete jug across Z, stir-in and drain.
Once drained stir-in X then drain again.

*I find that the grain actually absorbs less than 1 litre per kilo, but it’s still a useful starting point.

[Scooby]

Ignoring efficiency, quality of wort etc Simon's question was why does GW state 33.3l total liquor and Chris's calculator 37l or so.

1. GW assumes you are using a 'standard' boiler that will not boil 'all in' so his method it is to boil a manageable volume which means a top up of the fermenter is required. The fact that he mentions drain and 2 sparges has nothing to do with it.

2. Chris's calculator gives you the total preboil 'all in,' fine if the boiler has the capacity, if it doesn't the wort can be collected in jugs and added to replace losses during the boil.

You need to adopt one or the other, it's only when you compared 2 different methods that you found the anomaly.

[vacant]

The "wort required for boil" figures differ by only 0.4 litres. This difference is due to the way "loss dues to evaporation" is calculated. GW's beer engine takes it as a percentage of the "target volume" (23 litres), JBK's takes it as a percentage of the "Wort Required for the Boil" (25.6 litres). Therefore, entering "15%" is bound to give slightly differing results:

15% of 23 = 3.45
15% of 25.6 = 3.84
3.84 - 3.45 = 0.39 approx 0.4 litres

@SZM "Enter estimated loss to hops and trub 5 litres (ie matching 5kg of grain)" - I don't think so, this is meant to be what is left in the boiler. If you add the volume of water left in the mash tun (5Kg grain = 5 litres plus a little bit for the extra saturation in your mash tun dead space) then you get to around 37 or 38 litres total starting liquor.

[Scooby]

More confusing info.... Simon is referring to GW's book not Beer Engine.

[vacant]

More confusing info.... Simon is referring to GW's book not Beer Engine.

What? GW's beer engine does it differently from his book? I only use the software

[Scooby]

Yes. There is a vol required for the different batch sizes for each recipe. Obviously It doesn't get complicated and mention dead space, losses to grain and hops etc, but if his instructions are followed with regard to the boil volume and topping up the fv, then with the sort of equipment used by an average home brewer the recipe will produce a satisfactory result.

[SZM]

Thanks all of you for your replies - really helpful as ever and I will let you know how it goes!