How much does size REALLY matter?

I am looking to get back into brewing again. I took a year off and finally find myself being pulled back into it (not a terrible thing, whatsoever). I'm building up my equipment again, doing everything right this time . I want to eventually go big enough that I can start perfecting brews good enough for production. So here is the question: how big is too big for a 2 or 3 gallon batch? I want to eventually brew 10+ gallon batches. So can I get away with a 100 qt cooler for a mash tun, 15 or 20 gallon brew kettle and a 15+ gallon fermenter for 2 to 3 gallons?

Thank you for the input;
Chester
The E-burg Brewer, WA

I use 15.5 gallon kegs as my mash tun and brew kettle. It is a solid size for making 10 gallon batches. So, I would say a 100qt/25 gallon MLT and a 15 gallon kettle/15 gallon fermenter setup would be perfect for 10 gallon batches. Seems like it might be a bit of overkill for 2-3 gallon batches though. Makes me wonder if the 100qt cooler for a MLT would spread your mash to thin for a small 2-3 gallon batch which might affect your efficiency.

That was my concern. If I took a 100 qt MLT that has a large surface area, the 2 or 3 gallon batch may dissipate heat too quickly for a 60 minute mash. Would it be appropriate to match the surface area to mash ratio in two different containers e.g. 20 qt cooler and a 100 qt cooler?

I think you're trying to accommodate too large a of a volume variance; I can see doing 5 gallon and 10 gallon batches on the same equipment, but 2 gallon batches and 10 gallon batches on the same equipment is too large a variance.

Have you considered building your equipment for 10 gallon batches and doing your 2 gallon batches on the stove top?

A couple inexpensive stainless pots for stove top AG brews and your 20 gal BK 25 gal MT setup for 10 gallon batches?

As for fermentation vessels, you will have issues trying to use the same vessel for 2 gal batches and 10 gal batches - unless you partially void the air in the vessel with CO2 for a 2 gallon batch, you will risk oxidation IMHO.

Again, get an inexpensive vessel for your 2 gal batches (5 gal BB maybe?) and get a larger vessel for the 10 gal batches.

I can understand the want for one set of equipment, but I just don't see it happening with such a variance in volume, 5 & 10 gal batches on the same equipment could work, but not 2 and 10; just my thoughts and opinion.

NOW to try to make it work (since I like a challenge) if you use a keggle for a brew kettle and a 48-60qt "cube" cooler, or a second keg that you will insulate for a MT you could potentially do 2 and 10 gallon batches on the same equipment.

Boil Kettle issues
on 2 gallon batches you will have a lot of boil off and will have to compensate for it with extra water in the boil.
on 10 gallon batches you will have to watch it like a hawk for boil over.

Mash Tun issues
on 2 gallon batches - you will have to preheat the mash tun with boiling water to prevent too much heat loss during the mash. You will have to compensate for the increased inefficiency due to loss of wort in the mash tun.
on 10 gallon batches - high gravity beers will be difficult as far as space is concerned for the mash.

now if you have stainless steel insert open on one end that is the same height as your boil kettle you could use during the mash and boil, it will solve some of the 2 gal batch issues. Essentially it voids a lot of the space and reduced the impact of the issues; this would work for a two-keg set up, and would have to be weighted. Actually a 5 gallon sanke keg with the spear pulled out and some kind of weights on the top could work. It would reduce the surface area of the grains during the mash, as well as reduce the surface area of the boiling liquid, thus reducing the surface area and boil off. It would be another item to sanitize and clean but may solve your issues. I was originally thinking of 5 gallon ice cream cans, but I can't come across an image of them on the internet; I'm not even sure if they make them anymore...

good luck!

Get your setup for your 10 gallon batches and do your 2-3 gallon batches BIAB. In a 20 qt pot. You can get a suitable pot at the grocery store for about $20.

I have 5-gal/10-gal coolers for mash tuns. I have a very small SS 5-gallon stock pot for small batches and ciders, and an 8-gallon, a 10-gallon, and a 15-gallon for everything else. I probably use the 10-gal MLT and the10-gallon pot the most.

The 5-gallon pot is perfect for 1-2.5 gallon beers.

The 8-gallon pot is perfect for smaller 3-5 gallon beers

I think a 10-gallon pot is the sweet spot for a 5-gallon batch. You can do small or big beers in it pretty easily.

The 15-gallon pot is generally relegated to heating water for sparging, but if I ever go to 10-gallon batches it will come in handy. It's too big for doing smaller batches, but it's good for 90 minute boils.

I prefer my 5-gal mash tun and use it whenever I can, It's perfect for smaller beers and 1-5 gallon batches, but it is too small for bigger beers. My 10-gal mash tun is used for bigger beers, but doesn't hold heat as well as the smaller one.

It's sounding like the only viable decision is to have two sets of brewing equipment for the different sizes of brewing. My true concern is the difference in outcome taste with running two separate systems. Would matching the surface area to batch size ratio be enough to maintain consistency? Just to keep consistency.

Thank you for the input guys, it helps a lot with grasping differences in what to expect.

The difference in outcome could be negligible or vast depending on your attention to detail while brewing.
Variables that will affect your outcome (just a couple)
heat sources/thermal mass - you will be using different heat sources, so your heat up times will be different, your cool down times will be different, your temperature swings during the mash from temperature inputs will be different. The larger vessel will potentially hold temperature better due to the increased grain/water mass. One will happen outdoors one will happen indoors so ambient temperature will play a role.
efficiency/crush - since your volume of grain will be different any inefficiencies due to crush will be harder to correct in the larger batch, any inefficiencies due to mash temp will be harder to correct in the larger batch and these corrections will affect your final product (assuming you correct with DME/LME).

All of that malarky above stated, I've brewed in VT on an electric stove with a 18qt pot and a 12qt pot, in Brooklyn, NY on a gas stove with a 18qt and 20qt pot, in CT with a 32qt, 20qt, and 18qt pot set up; if I do the same recipe and use the same water, my beers come out generally the same. I accidentally tested this with my "Vermont Maple Porter" I used 6 gallons of Vermont pure water, some Grade "B" maple syrup from the same farm in Vermont, and the same grain bill (although from different sources) it started out as a nostalgic recipe when I moved from Vermont to Brooklyn, then when I made it again in CT I realized it was more of a control batch. Each time, it is more or less exactly as I remember it, however i haven't made it back to back (i.e. made it in Brooklyn, then moved to CT and made it right away), however, as a control, it's pretty spot on; unless my memory is not to be trusted.

So yeah, I honestly think you can make very much the same beer on two separate systems if you scale the recipe properly, and recreate your process accurately - if you overshoot by 2 deg during the mash on your smaller system, do it on the big system, etc.

DO IT and come on back and tell us how it went