Mini All Grain, how to calculate top up?

[RobWalker]

Hi all,

Due to a course of medication I'm almost unable to drink (no sympathy guys, I still get the odd few in!) and I've started brewing 2 gallon all grain batches.

As it recently occured to me that I would be better off using a sort of brew in a bag - coolbox hybrid method to maintain mash efficiency and keep costs low, I'm going to be upgrading to that. I'll mash in the coolbox with a grain bag, then sparge the grain in a plastic sink bowl with holes drilled in it. This way, I'll almost definitely hit efficieny.

This is all well and good, but how would I calculate how to top up after boiling? Here's a quick run down of how I work;

Mash grain in cool box
Sparge into cool box
Tip wort from cool box into boiler. Boil 11L wort
Top up back to 11L after boil is completed.
Cool in ice bath.
Drain through tap into 2 gallon FV.

I'm currently overshooting my OG on purpose, so I'll be aiming for, say, 1.055 OG pre-boil, and topping back up to this volume after boiling. I can assume that leaves me with a post boil OG of 1.055, but how would I calculate the IBU, colour etc accurately? could I do this by setting my boil off rate to 0%? Any particularly bad effects to topping up a few litres I should watch out for?

Thanks in advance, hope this topic doesn't confuse!

[Normski]

Hi Rob

Sorry to hear you have been unwell. You can use Graham's Beer Engine to adjust your recipe's quite easily.
Its a free program and works well. You can change the size of the brew and it will give you the new quantities.
You can find it at the top of the page in Calculators.

Norm

[PaddyX21]

Are there any serious disadvantages to brewing 2gal AG batches?
This would allow me to brew AG with the limited space / equipment that I have around, which obviously appeals to me greatly!

How has it been working for you RobWalker?

Cheers
P

[Normski]

Hi paddy

Until Rob tells you how he is getting on with his. I have made small batches and to be honest it takes up just as much space and exactly the same time as a larger batch. The only difference is you end up with less beer.
For me, I can see no reason to do less than 23l. The amount of work done in a brew day deserves at least 23l of beer.
If you are doing experiments, then maybe doing a smaller batch is ok. It could save ending up with large amounts of something that is not as you had hoped.

Norm

[PaddyX21]

Thanks Norm, I do see where you are coming from.
Also with smaller batches then accuracy could become an issue I guess, with small differences in weighing for example leading to much higher percentage changes in the overall formulation, making any repeatability an issue!
I'll see how things progress, I may still start with small batches to get me going, and save up for larger equipment for the future.

I was warned this could be addictive (and therefore expensive)...

[darkonnis]

Rob, you might be better just sticking to biab if you have a pan big enough, failing that: You can't very easily determine hop bitterness once you start topping up AFTER the boil. If it where me, I'd look to top up while its boiling using boiling water from a kettle, that way you can ensure everything has been boiled and any top up water has atleast had chance to come into contact with the hops. If you keep the volume the same your OG will be roughly the same give or take a few points.

Paddy, you're best bet is to get a 20L stock pot and go from there, I did 2 gallon batches in a 15L and it was a PITA because of the lack of space in the pot, getting the grain out as a result become messy as there was no way to get the bag out of the water whilst also keeping the lower edges in the pan, which would have stopped quite so much wort running everywhere. It is something I'm going to revisit but that is certainly how I'd look at doing it.
Accuracy is a bit of an issue, but as long as you dont expect it to be quite the same when you scale it up you'll be fine. Just might take a few goes to perfect it is all.

[RobWalker]

Hi! don't hang around here much so thought i'd update, albeit very late;

anyway, my solution was to simply use my pre-boil readings as my post boil readings and top up to the same volume after boiling. in beersmith, that's setting boil vol to 10L, setting batch size to 10L, and you get the IBU and OG estimate easily. seems to pan out quite well!

I like it. It needs less lifting and specialist equipment, it's very fast to return to the correct temp on the hob should you lose temp, and the small batch size allows me to tweak my recipes often and brew regularly.

as for hops, you're gonna struggle with high AA% bittering hops as a gram can make all the difference. but use something like Saaz for bittering, and accuracy becomes a little less important - you may also struggle with brews with lots of hops, as they soak up so much of the wort and it all becomes like a big pot of porridge

but all said and done, I brew all grain with little more than a 12L pot, towels for insulation, a standard grain bag, plastic 2 gallon fermenter, a syphon and my trusty bottles and caps. the beer is noticably better, and it may wet your whistle for bigger scale all grain brewing. there's certainly not much volume, but there's something very special about a 15 bottle batch that depletes very quickly.

for the record, I'm well on my way to recovery and drinking again! it was really only precautionary anyway, and whilst there's much to sort out, i'm a lot better than I was a month ago