All Grain - batch size?

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MaltyMat

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Hi,

I have just started all grain brewing :grin: . My first attempt wasn't too bad, but I found that throughout the process (boil, sparging, cooling, transferring etc.).I lost about 10 -11 litres of liquid. and had to top up with boiled water to get back what I lost, and also ended up with less than full secondary fermenting container :( .

This time I want to try and start off with more wort so at the end of the process and fermentation have at least 23 litres in my secondary fermenter (so I have a very little air gap, and hopefully less chance of the beer being oxidised after fermentation). Calculating in my losses from the first time I have worked out I would need about 34 litres of wort before sparging.

Here's my Question :hmm: :

I use brewing software "Qbrew" to calculate my recipe for bitterness, colour, and Alcohol content etc, and these factors all seem to be determined by the batch size, quantity of grain and hops. What I was wondering is, if I need 34 litres of wort before sparging to get my final amount of beer in the secondary fermenter to around 23 litres, should I use 34 litres as my batch size for calculating the bitterness, colour, amount of grain and alcohol content of the recipe?
 
I use BrewMate, but believe I'm correct that batch size is how much you end up with in your fermenter.
The key is working out how much liquid you lose at each stage of the process, so in the mash you lose near enough 1L per kilo of grain, you'll lose a little to the dead space in your mash tun. You lose to evaporation in the boil, your hops absorb an amount of wort, you evaporate a percentage off during the boil, when you cool the wort it "shrinks" so you lose volume there (2%ish I believe) and again there'll be some dead space in the boiler.
The dead space can be found by putting some water in your mash tun / boiler then running it off via the tap and measuring how much is left when the flow stops, loss to evaporation by how much you have in the boiler pre boil minus post boil, loss to hops is one I still struggle with but you're looking at 1.5-2L per 100g of hops. Once you know what you lose then you know how much water you need to start with.
 
Why do you need to be at 34 ltrs before the sparge? Usually during an all grain brew you sparge until you've reached either your pre-boil gravity or your desired kettle volume. For instance: I know I loose 1 gallon per hour in the boil and 1 gallon in trub, so my pre-boil kettle volume needs to be 7 gallons for a 5 gallon batch. I've gotten to the point of not worrying about my sparge water, and just start with 12 gallons of sparge water in the hot liquor tank. I usually finish the sparge with 3-5 gallons left in the HLT to use to clean out pumps and hoses.

If you have a specific volume for your pre-boil then adjust the grain bill so you are getting as close to your numbers as possible and hitting that volume by the time the sparge is complete.

Don't get discouraged; I've never met a brewer who learned his system in the first 6 months of all grain brewing. Welcome to all grain!
 
Thanks for all of your replies.

I think I understand a bit more, just trying to get my head around it.

If I understand this correctly the batch size is the volume of wort before fermentation, and the recipe calculations takes into account the reduction of the liquid from liquid absorbed form the gain, hops, and the boil off from the amount of time used for hop boil. So if I work out my losses correctly and compensate for this in the amount of water used for sparging, to get my wort before fermentation to 23 litres and I have used 23 litres as my batch size for recipe calculations, then my beer colour, bitterness and required starting gravity before fermentation should be spot on?
 
You are getting a bit closer, but grab another pint and pull up a chair, this tends to get a little confusing at times.

Your batch size is the amount of boiled and cooled wort you are running off into the fermenter.

So, let's say your desired goal is to have 23L in the fermenter at the end of the brew day. First we need to make sure your hot liquor tank can accommodate 23L + 1/4 of your desired end product. We will say a 30L pot would be perfect for your hot liquor volume. Now since your HLT has the capacity to bring your desired kettle volume up to 23L, fill that bad boy up and get the HLT up to 81* C. Now you have plenty of water to rinse the grains with after your mash. Depending on your setup you will next need to add the correct grain:water ratio in your mashtun according to your recipe and mash efficiency. I don't know if you have a direct fire mashtun or something like an igloo, but somehow get the mash water 10* higher than the the temp you want your scarification rest to be held at. So, if your target mash temp is 66* C, then your strike temp should be around 72-75*. Once you dough in the temp should drop with the amount grain mixed in.

Ok, so all the busy little enzymes in the malt have converted all the complex sugar chains to much simpler ones, it's time to kill those enzymes. Bring the mash up to 76* to stop the enzymes, and hold it for 15 min. Now depending on if you fly sparge or batch sparge, start your runoff from the MT to the kettle and start sparging at the same slow rate. This is where a lot of liquid gets lost. If you are fly sparging then keep about an inch of water above the grain bed, and runoff about 1L per 3 minutes. Yes, this is a long process, but you want to be sure and rinse all the sugars from the grain without extracting unwanted proteins or tannins. If you are batch sparging, just open the MT into the kettle and start running your sparge water through the mash.

Now the important part; you need to know what your pre-boil gravity is going to be prior to running off. Mine is ten points higher than my OG, but that's just mine on my system. You should also have your kettle calibrated either with a measuring stick or a sight glass. This way you know when you've hit your pre-boil volume.

The water loss from the grain has already taken place, so you don't need to worry about that. Next you need to figure out how much liquid you loose to steam during the boil. Typically it's 1 gallon per hour. We also need to look at how much wort you leave behind in trub. This is normally 1-1.5 gallons. So, with these numbers already figured out you now know you need 31L in the kettle before you boil for an hour. That should put you at a post boil volume of 24L leaving 3.5L in the kettle as trub.

I hope this helped, and did not just add to the confusion.
 
Thanks artiums_enteri, very good explanation.

Looking over it all, my main worry was I didn't understand how my brewing software calculated the IBU's in the recipe or about the standard formulas (Rager and Tinseth etc.). But I now have read up on the formulas and see that they all use the final batch volume, and not a starting volume. As you say the loss during the boil off is around 1 gallon per hour and this must be factored into the IBU formula.
I was concerned that if I used batch size of 24litres with my brewing software that the IBU calculation formula may have used this as a starting volume then removed the volume losses during boiling for the bitterness calculation and I would have ended up with a more bitter beer than expected.

Now I understand that it is all calculated from the final batch volume (i.e. the volume of wort before fermentation).

Off to create my recipe... :thumb:

Thanks all.
 
No problem glad I could offer some help.

Beware of brewing software miscalculating IBUs though. I'm not sure about the software that you are using, but for some reason Promash, Beer Smith, Beer Tools, and even Brew Pal which is what I use on the iPhone for some reason calculates dry hop additions as IBU additions. This never made sense to me because dry hopping just adds the aroma of the hop, and very little AA is dissolved into the beer.
 
artiums_enteri said:
You are getting a bit closer, but grab another pint and pull up a chair, this tends to get a little confusing at times.
:D :lol:
Good points well made Art.
S
 
Springer each time I see your avatar I get the urge to go upland bird hunting and scratch behind your ears. I love it.

Prost!
 
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