I want to make 19L of coffee

Want to talk espresso but not sure which forum? If so, this is the right one.

#1: Post by cardrona10 »

I homebrew beer, and have a corny keg setup, but I'm not drinking as much beer these days so I was wondering if I could fill one of those kegs with coffee for convenience.

Of course, making 19L of espresso in 30ml batches at a time will be a massive PITA, I was thinking of maybe brewing it all at once, such as by cold brewing, but I thought I better ask what the best way of going about that would be?

Any input would be appreciated

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#2: Post by TomC »

When Blue Bottle Coffee finally decided to transition into the cold brew, highly extracted coffee realm to be diluted with milk into their convenient cold brew pre-packaged coffee, they had to come up with a method that allowed for consistency and accurate extractions in order to deliver those tiny pints of cold coffee extract and milk.

They started out here in the bay area by setting up hundreds of 5 gallon jugs as a back up method of extraction, while renting the local beer brewers industrial machinery for beer making, converted to high EY extraction coffee brew during the PM hours that the beer brewer was offline. This was done for only a brief period of time until their proof of concept was fully developed and on-line. To my knowledge, even though they'd set up with hundreds of 5 gallon plastic jugs, they never needed to revert to them to get their product created. Those were just setup as a standby incase of some emergent crisis of production.

At nearly 20 liters of expected output, I don't think anything on the market will currently support that. I do have a previously declared bias of knowing and befriending the creator of Voga Coffee's Ground Control brewer that can make highly precise concentrated coffee that will yield extracts that liken to espresso and high EY brew for cold brew coffee, in a much more convenient. short timeline, hands off method of extraction. I'd seriously motivate and push anyone interested in this sort of high extraction brew towards this system, since there really isnt anything else on the market that can deliver anything similar.
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#3: Post by Jeff »

Not likely practical for your needs, but one of those "worth a watch" explorations of commercial-scale production

The craziest %#*$ing thing I've seen all day...

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#4: Post by bostonbuzz »

I mean, if you can heat water to 200F and pour ground coffee in and then filter out the grinds, you have it made. Presumably that's what Tom is alluding to with Blue Bottle. I think giant brew gear can also agitate and stir right?

You can also get a plastic bunn filter holder on ebay for $5 and put a filter in it and do a giant pourover with a pitcher of hot water (what all cafe batch brew machines do). You'd probably only need about 3-4 of these to get 19L.

Cold brewed coffee can be a bit blander than flash (hot) brewed coffee brewed to higher concentration and then diluted with ice in the container FYI, so if you don't want acidity go cold-brewed.

In my cafe I had an employee who demanded we do toddy from their time at another cafe. I bought the system, dialed it in, and had a blind taste test. The toddy was good but bland, and the flash brewed using a Curtis G4 was much tastier and fruitier.
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#5: Post by cardrona10 (original poster) »

@bostonbuzz, Yeah I have a personal brewing machine I can use to precisely heat the water and re-circulate it through grains to extract carbs for beer, which I can probably also use for coffee, just wondering about the difference between flash brew and cold brew, to see which one would better suit my needs.

I was watching this documentary on Tea, and they talked about cold brew, and even leaving the tea on ice so it could extract that way, and while it was a bit blander, it also extracted less tannin, which may be more palatable if i'm (likely) drinking more of it.

What would be the more technical science to it? Is there an optimal temperature for flash brew which has a different effect on the taste of the coffee I can set my machine to? I've also heard that the best way to make coffee is to extract as much coffee "oil" as possible with the fewest amount of tannin, is that true as well?


#6: Post by Jonk »

Do you drink more than 2L on average per day? Cold coffee has a limited shelf life*. If you can keg with nitrogen, a little longer - plus you'll be able to pour coffee with the looks and texture of stout :D

Figure out if you like cold brewed to flash brewed coffee before you try to scale it up. I'd suggest to stick with immersion for simplicity. You can then make cold brew in a bucket or fermenter with a mesh bag, or try using the same mesh bag in your brewing system if you prefer it flash brewed. Recirculation might be unnecessary, just start with off the boil water, strain after a few minutes and chill like you would with wort.

If you use a floating dip tube in the keg it's probably fine not to bother filter out the finest particles. They will sink to the bottom, think of it like dregs.

*low oxygen brewing techniques could help some.

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#7: Post by bostonbuzz »

cardrona10 wrote: Is there an optimal temperature for flash brew which has a different effect on the taste of the coffee I can set my machine to? I've also heard that the best way to make coffee is to extract as much coffee "oil" as possible with the fewest amount of tannin, is that true as well?
No, it's just normal coffee making. ~200F to start.

Not sure about the tannin thing. You are doing nothing different than what everyone posts on here about the thousands of YouTube videos on pour over or immersion brewing, just a larger scale and less water and a much finer grind.

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Here is a video I found on flash brewing, the challenge is mostly in finding the right grind size which needs to be very fine to get enough extraction with so little water.

Like I said, cold brewed will not have much acidity and the associated flavors. Coffee is extremely complex and those things need heat chemically to be released.

I'm not saying one is better. For beer brewing if someone wants a "coffee" stout/ipa, etc. They expect that strong 1st wave coffee flavor. I've also had beer with actual espressos in them and 3rd wave light roasts which were good but non typical- lots to experiment with.

I agree with the previous poster, dial in some flash brew and then compare it with cold brew. Simply dump some grinds into a container overnight and filter in the morning. Try a couple different grind settings. Plenty of info online.
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#8: Post by braxtonjens »

Just my 2c...
Make the coffee in a big pot/ vessel like a cupping or French press. (Sounds like you have all the stuff for this since your a beer brewer)

Then after the grinds have settled pour or gently siphon off the top, making sure not to get the grinds mixed back into the brew/ filter it if needed then go right into a keg.
Purge the keg from O2 with nitrogen. Throw it in the fridge and call it good.
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#9: Post by yakster »

The basics of flash brewed coffee is to brew the coffee hot with less water and then cool it by brewing it into ice. You may have an option to brew coffee at full strength and run it through a wort chiller to cool it down. I prefer flash brew over cold brew, cold brew us muted and has a certain funk to it most of the time where flash brew preserves the bright flavors and acidity of the coffee.

Here's a couple of my larger flash brew recipes.

5. Brazen iced coffee recipe v3
60 g coffee
550 ml water
340 g ice (~14 tray cubes)

10. Double "Alcatraz" Iced Chemex
80 g Ethiopian Chelektu Yirga Cheffe
566 ml Water
392 g Ice (~16 tray cubes)

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#10: Post by yakster »

One thing to keep in mind is that the coffee won't keep forever. Probably a week or two.

Are you thinking of doing a nitro cold brew with a stout tap?

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