Coffee and Tea -- Kegged and Awful

[AlexKay]

Hi!

So with the arrival of a new keezer, I finally have spare taps for coffee, tea, sodas, and whatnot. I brewed a batch of tea and a batch of cold-brew coffee. (Tea: bring water to 205 F (not boiled and then cooled), steep leaves for 3 minutes; Coffee: add grounds to room temperature water and steep for 18 hours.) The coffee tasted good initially but went bad after one day in the keg. The tea lasted two days. Both have the same off-flavor, which I find hard to describe. It's kind of what you'd imagine drinking from the bottom of a dumpster would taste like. Garbagey.

Is there something big about sanitation or added preservatives I'm missing? I've never had beer develop off flavors in the keg, but the beer is boiled extensively as well as hopped.

Thanks in advance.

 

[AlexKay]

A day later, the taste is even worse. Argggghhh.

 

[Velnerj]

I have never done what you're attempting but to my experience there's not too many things worse than old coffee or tea. Some things are just made to be made and then consumed fresh....

 

[Beernik]

I have not done this either. I’d like to keg cold brewed coffee, but what cold brewed coffee I have drank isn’t as strong as I like coffee. So I don’t know if I’d need to “fortify” it with espresso or what.

Could this be your problem, though: beer gas or CO2 instead of pure Nitrogen?

https://www.homebrewtalk.com/threads/sour-cold-brew.675154/

 

[SoulToast]

Interaction with CO2 is at least a source if not the source. I did a cold-brew coffee on nitro, nitro ran out (stupid tiny, expensive nitrogen cartridges...but I digress..) so I hit with CO2 to push it...blech.

That carbonic acid bite that’s great in sparkling waters is...well, it’s total ass in coffee. And if your source coffee is a Kenya or something else with bright, semi-acid notes you’re gonna have a bad time.

 

[AlexKay]

Still mulling this over. Starbucks serves nitro cold brew, which means beer gas, doesn't it? Which means CO2, so I'm wondering how a low pressure (<5 psi) would cause problems. And I've had carbonated iced tea before, which doesn't mess with the flavor too badly.

I tried a batch of tea with a bunch of hops, which will test the preservative theory. But while I rather like hops, not everyone does ... I'm probably going to try straight nitrogen next.

 

[codysorgenfrey]

Still mulling this over. Starbucks serves nitro cold brew, which means beer gas, doesn't it? Which means CO2, so I'm wondering how a low pressure (<5 psi) would cause problems. And I've had carbonated iced tea before, which doesn't mess with the flavor too badly.

I tried a batch of tea with a bunch of hops, which will test the preservative theory. But while I rather like hops, not everyone does ... I'm probably going to try straight nitrogen next.

A nitro system is different than a CO2 system. It uses nitrogen gas with different taps and a different tank/regulator.

 

[Beernik]

Nitro ≠ beer gas.

Beer gas ≈ 70% Nitro + 30% Carbon Dioxide.

 

[AlexKay]

Yes. And I agree that straight nitrogen may be the way to go. But I thought Starbuck's "nitro" cold brew has a big head and lots of little bubble, which implies beer gas and a creamer faucet to me. Just nitrogen shouldn't really give any bubbles at all.

 

[AlexKay]

Interaction with CO2 is at least a source if not the source. I did a cold-brew coffee on nitro, nitro ran out (stupid tiny, expensive nitrogen cartridges...but I digress..) so I hit with CO2 to push it...blech.

That carbonic acid bite that’s great in sparkling waters is...well, it’s total ass in coffee. And if your source coffee is a Kenya or something else with bright, semi-acid notes you’re gonna have a bad time.

Well, I was skeptical, but not too skeptical to go get a tank of food-grade N2 and a regulator. And now I’m on my way to being convinced … tea and coffee both kegged on N2 and flavor-stable at least for a few days. Unquestionably better than before.

 

[archi77]

Yes. And I agree that straight nitrogen may be the way to go. But I thought Starbuck's "nitro" cold brew has a big head and lots of little bubble, which implies beer gas and a creamer faucet to me. Just nitrogen shouldn't really give any bubbles at all.

CO2 should never be used with coffee. It makes the coffee oxidize (or whatever the scientific term is) and taste bad, in my experience, almost immediate. The nitro faucet will introduce the tiny bubbles, and pure nitrogen is what Starbucks uses for their cold brew (only know because I asked once). I’ve never tried tea this way, but love a good cold green tea, so might experiment.

<edit for spelling error>

 

[crazyjake19]

Seems like you've got it figured out, but you definitely never want to use CO2 or beer gas mix with coffee - only straight nitrogen! I make 3 gallon batches of cold brew coffee (18-24hr @ 38-40F) and keg with nitrogen. Usually a keg doesn't last more than 2-3 weeks but even on the third week it tastes just as good as the first day.

I did nitro cold brew originally with a high serving pressure and a nitrogen/stout faucet. It was cool with the cascading effect, but I found to be going through nitrogen too fast, so I just serve it around 6-8psi now with a regular draft faucet. Not as cool as true nitro cold brew, but my nitrogen tank lasts way longer.