Tips for scaling DOWN to small batches....

[DVCNick]

I'm probably not the only one who's ever thought of this, but I imagine most people go in the other direction.
So far I've only done five and ten gallon batches (yes, even going back to my partial boil extract days).

Lately I've been entertaining the idea of doing smaller batches, and now in particular I'm thinking of shooting for a 1.75 gallon batch to fit the mini keg on NB website. Upsides that I can see:

-My kitchen stove can maintain boil on at least 2.5 gallons, so if I do BIAB on these, I can brew without dragging out the propane/burner, mashtun, HLT, chiller, etc
-Without having to run out to the garage all the time I'll be able to multitask while doing other things in the house, further reducing the time impact footprint of the brew day
-It will give my old 5 gallon kettle something to do.

Has anyone done this, and if so, what issues did you run into? Things that I'm envisioning will take experience to get right:

-Volumes. I'm decent now (not perfect) on hitting volumes for 5 and 10 gallon batches, but with the smaller BIAB the variables are going to change, and even samples... if you are doing a preboil, OG and FG, that is going to be ~1/15th of your final volume all by itself... For those that have done this, any thoughts on how to get this close on the first try?
-Yeast - do you just do a smaller starter for liquid? Use half a pack or so for dry? Is storing an open dry pack considered sanitary?
-Do you HAVE to crush finer for BIAB? (I have never done BIAB)
-Fermenter size - is a 6.5 gal carboy acceptable for a ~2gallon batch?
-Keg - can I trial this in a regular 5G keg? I would assume getting the headspace purged is the biggest concern, but as long as I liquid purge it and drain in through the liquid port I think it would be ok, aside from the subsequent waste of CO2 pressurizing all that headspace?

Any other thoughts? Thanks

 

[kevin58]

I do this during the winter. My 5 - 10 gallon system lives in an unheated garage and I get my water from the outdoor faucet about 30 feet away at the house. In the winter my garden hose freezes and I ether have to haul water from the house out to the garage... not going to happen. Or brew indoors.

So I resurrected my old extract brew kettle from 20+ years ago and do small batch BIAB on the kitchen stove. I make 2.5 gallon batches. I ferment in 4 gallon drinking water jugs... the kind used for office water coolers that you can buy at most big box home stores. Since there is only about 18 bottles worth of beer in the end I dusted off my bottling equipment and that's how I spend my winters. I usually make styles I have never tried before or original recipes. If they turn out well enough I will ramp those up to 5 gallon batches when the weather gets warm. To create the recipes I went through the process of creating a small batch equipment profile in Beersmith 3. To scale larger recipes I just use the scale recipe tool in Beersmith. Since everything I use are tools I already have on hand the only thing the whole set up cost me was the water jug from Lowe's.

 

[BrewnWKopperKat]

-Volumes. I'm decent now (not perfect) on hitting volumes for 5 and 10 gallon batches, but with the smaller BIAB the variables are going to change, and even samples... if you are doing a preboil, OG and FG, that is going to be ~1/15th of your final volume all by itself... For those that have done this, any thoughts on how to get this close on the first try?

For pre-boil SG & OG, I use a refractometer. For FG, a finishing hydrometer uses 3 oz per measurement. You'll also want to account for malt/hop trub, and some amount of beer lost during transfers. Maybe 2.25 gal (including trub) in the kettle at the end of the boil?

-Yeast - do you just do a smaller starter for liquid? Use half a pack or so for dry? Is storing an open dry pack considered sanitary?

For 2 gal batches, I've used 1/2 of a 10-11.5 gram package.

I find that open packets of dry yeast store well in the fridge for a couple of months (typically I brew often enough that I haven't had a package open longer than a couple of months). I just close the package tightly and 'secure' it with a rubber band.

-Do you HAVE to crush finer for BIAB? (I have never done BIAB)

No need to crush finer. I get slightly better efficiency when I "double-crush".

 

[DVCNick]

Thanks... so let me know if I'm missing anything here. Just a sanity check....

I did a boil off test starting with 2.5 gallons and lost about 1.75 quarts in an hour.
Since it will be BIAB the variable for mashtun deadspace will be zero.
Use my normal grain absorption rate number which is about .4 to .5 qt/lb of grain.
I'm assuming the smaller total volume in the fermenter will yield less loss to trub scaled linearly.
Loss for hydrometer samples

Is there anything else I'll need to consider to work backwards to a correct target starting volume?