Reducing batch size

[DanOmite]

Hello, when I'm home with my friends we usually brew 5-gallon batches, but I live in a very small apartment at school with a dinky kitchen. One of my friends has an old Mr. Beer kit and said I could take it back with me. The tank it comes with is only 2 gallons, but that’s perfect for me. The tank is all I really need. I have all the pots and a supply store for the extract / grain and hops.

So, my question is: how do I convert my 5-gallon recipes to 2-gallon recipes?

I would think I just reduce all ingredients and amounts of water by 40%, but I have a feeling there is more to it. I have heard of people messing up recipes when they scale up, so I’d imagine the same happens when scaling down. I am particularly worried about the hop additions (I tend to brew hoppy strong ales).

Anyone have any experience with this? I’d appreciate some advice. Thank you.

 

[StrmStlkr]

I have no experiance in this but if it were just a linear adjustment it should be a reduction by 60%, not 40%. I agree with you though, I imagine there is more to it than that. Will have to let the more experianced brewers chip in on this one.

 

[Frodo]

You can scale down by simple proportions as long as you can boil the proportional volume; so in that case multiply the 5 gal ingredient amounts by 0.4. If you couldn't boil the proportional amount of wort for some reason, you might want to scale up the hops a bit to account for less hop utilization in the denser wort, or do a late extract addition.

 

[Pommy]

I would recommend buying another primary because 2 gallons really isnt often enough. Apart from that if you are going to do 2 gallon batches then just multiply your weights by 0.4 and make a good starter with half a pack of yeast at a time because buying a full pack of yeast for 2 gallons sounds expensive to me.

 

[demonrichie]

I would recommend buying another primary because 2 gallons really isnt often enough. Apart from that if you are going to do 2 gallon batches then just multiply your weights by 0.4 and make a good starter with half a pack of yeast at a time because buying a full pack of yeast for 2 gallons sounds expensive to me.

depends on what yeast youre buying and if you are paying for shipping. dry yeast is not too expensive at my lhbs id buy a pack for a 3 gal batch. besides if your worrying about space there is always space you just have to improvise i got my swamp cooler stashed beside my sink in the bathroom no probs and its easily big enough for 2 large buckets for 6 gal batches and my 3 gal. and if you saw what ive stuffed in my apartment yours would seem like a mansion... others have stashed fermenters behind couches too if your wondering

 

[smallbatch]

Per my name, this is kinda my thing now...

Before I get into more detail, if all you want is the easy answer (though not the one that will help you "make the best beer possible"), the Beer Recipator can scale recipes for you easily.

I'm at the one gallon scale and I can point you to a couple articles that I've found helpful in my endeavor:
http://www.byo.com/stories/techniques/article/indices/19-brewing-tips/1410-small-scale-brewing
http://www.razebrewing.com/go2/small_batch_brewing/

The most important points:
Scale most everything by 0.4 (2 gal / 5 gal). Take special note that you can no longer really go by the "eyeballing" of 1/2 an ounce or so of hops for your additions. Now you really need some sort of scale and measure in grams (for increased precision). Also beware of overpitching. Check out Mr. Malty's pitching rate calculator to keep you straight on that.

Whether you're doing small batches, big batches, or "average" (5 gal) batches, think about some sort of brewing software (if you don't already have it). Qbrew is free and I used it for a long time (though I've recently taken a liking to the not-free BeerSmith). This will allow you to make a sanity check on your scaling (by checking gravities, IBUs, colors, etc.)

If you're like me, you'll really enjoy these smaller batches. You can turnover a batch much faster, allowing you to tweak your recipe much more quickly and give you more chances to do actual brewing (what I find to be the funnest part of the hobby). Also, you can do the all-grain route without all of the equipment you would normally need. If you want to PM me, I'll give you more detail, but this post here is awesome for working your way to that route: https://www.homebrewtalk.com/f39/easy-partial-mash-brewing-pics-75231/.

Many people told me "why do all the work for 1/5 the beer?" but when that "work" is fun (and you actually save a lot of work on the bottling) it's not such a sacrifice.

 

[smallbatch]

...If you couldn't boil the proportional amount of wort for some reason, you might want to scale up the hops a bit to account for less hop utilization in the denser wort, or do a late extract addition.

Any IBU calculator is an educated guess at best, so I'd say give it a whirl with your current recipe and just modify as you see fit based on the results. As I mentioned before, the smaller quantity will allow you to iterate over your recipes much more quickly, allowing this kind of modification to be applied much more quickly.

 

[DanOmite]

I have no experiance in this but if it were just a linear adjustment it should be a reduction by 60%, not 40%. I agree with you though, I imagine there is more to it than that. Will have to let the more experianced brewers chip in on this one.

Where are you getting 60%?

Thanks guys for the help. Also, I will be at a higher elevation; 7000 feet to be exact. I'd assume I have to reduce all the temperatures in my SOP by some amount, which I can probably find in my old chemistry textbook or something. Would this be correct?

Also, would it hurt to throw in a full pack yeast for such a small brew? I notice there was some discussion of this in the preceding posts.

 

[Frodo]

Where are you getting 60%?

Thanks guys for the help. Also, I will be at a higher elevation; 7000 feet to be exact. I'd assume I have to reduce all the temperatures in my SOP by some amount, which I can probably find in my old chemistry textbook or something. Would this be correct?

Also, would it hurt to throw in a full pack yeast for such a small brew? I notice there was some discussion of this in the preceding posts.

No need to adjust for temperature with anything. The elevation being 7000 feet compared to sea level just means your wort will boil at a slightly lower temperature than 212 F, which doesn't affect your SOPs. Enzymes will still convert starches etc at the same temps as they would at sea level, if you're doing partial mashes or whatnot.

 

[Frodo]

You're actually going to get better hop utilization from a denser boil.

That's incorrect. You put that link in there to the wiki, which doesn't say what you apparently think it says.

What it DOES say is that the larger the boil the better the hop utilization. Translation: the less dense the wort the better the hop utilization, or in reverse, the denser the wort the less the hop utilization. Just sayin...

 

[smallbatch]

I have no experiance in this but if it were just a linear adjustment it should be a reduction by 60%, not 40%. I agree with you though, I imagine there is more to it than that. Will have to let the more experianced brewers chip in on this one.

Where are you getting 60%?

I scratched my head at this for a while also. I'm pretty sure it just comes down to semantics (or technical correctness). You said you would reduce by 40% when you should have technically reduced by 60%. I.e. a reduction of 40% (100% - 40%) means you would end up with a 3-gallons-worth batch of ingredients instead of the 2-gallons-worth you meant to achieve. Technically a reduction by 40% results in: (1-.4)*5, while a reduction to 40% results in: (0.4)*5.

In any case, I think you'd both end up with the same results given the same recipe, the terminology is just inconsistent.

 

[smallbatch]

That's incorrect. You put that link in there to the wiki, which doesn't say what you apparently think it says.

What it DOES say is that the larger the boil the better the hop utilization. Translation: the less dense the wort the better the hop utilization, or in reverse, the denser the wort the less the hop utilization. Just sayin...

You're right, Frodo. My apologies (along with an edit to reflect).

However, my point stands: take advantage of the small batch to taste the effect of any change of boil density.

 

[DanOmite]

One last question: since I am dealing with a small batch should I work with two gallons during the whole process and just top off the tank at the end if it looks a little low?

Thanks for clearing that up smallbatch. I should have seen that, I am graduating this winter with a degree in mathematics (emphasis in statistics / probability). My bad…haha.

Thanks for the help everybody. I really appreciate it.

 

[Frodo]

One last question: since I am dealing with a small batch should I work with two gallons during the whole process and just top off the tank at the end if it looks a little low?

The "best" way would be to measure the OG with a hydrometer to tell you whether to top off or not, especially if you're doing partial mash batches. If you're only doing extract batches, then you can reliably estimate what the gravity is without measuring it (by doing the math yourself, or with software) and just go with what your volume is supposed to be at the end - if that means topping off, then do so. Hope that helps.

 

[944play]

buying a full pack of yeast for 2 gallons sounds expensive to me.

...but for the convenience of being able to direct-pitch a proper cell count!

Harvesting and reusing yeast is a great way to lower batch cost, and in my experience it just makes better beer. Some wisdom that stuck with me from reading the ProBrewer forum:

yeast is your only raw material that will reproduce itself