Think.I agree with your line of reasoning, a quick test without direct contact between water and or ice and or dry ice should be doable and worthwile.
something like stirring hot beans in a large cooled metal container or the likes might do the trick.

I like the liquid nitrogen idea. Yes, it'll boil and splash like crazy, but as a lab experiment I think it would be worthwhile to carry out. If the results are promising, someone in the coffee research arena might pick up the idea and conduct some real research.

I have been dealing with flash-cooling "things" in liquid nitrogen for decades, but admittedly not a handful of objects with a temperature of 200°C. Perhaps simply tossing some liquid nitrogen onto the beans - rather than tossing the beans into a bucket of LN2 - could work to quickly get the beans to a temperature that is below the threshold for further internal roasting. I think that's all that's needed.

Check out the chemistry or biochemistry department at a university nearby. I am sure you'd be able to find someone willing to give it a "shot".

weebit_nutty wrote:Alas, it seems the quenched roast is found to be unsuitable for espresso. When I did my initial tasting, I used standard SCAA cupping procedures. I did not do any actual normal brewing.

Despite my favorable impression from the cupping, the quenching seemed to have drastically affected the bean composition. When I went to grind them in my HG One, the beans took significantly longer to grind--kind of like beans that were way too oily--except these weren't oily. Anyway this observation raised some concern for me, but nonetheless I proceeded with the prep and attempted to pull a shot on my Livietta. Yikes.. disastrous. So much so I didn't even bother trying to dial it in. The closest I could describe the extract is faucet-like

For drip, it seems fine, no weird issues. I the remainder of the roast for morning brews this week. See if I the wife notices a real difference or if I'm drinking my own Kool-Aid

According to the latest discussion on Pergers posts, it would suggest that you have created a bean that is highly soluble as we say. Perhaps it would be worth dialing it in afterall?

If it requires a finer grind, that would suggest less solubility. That and difficulty in grinding are two of Perger's hallmarks of underdeveloped roasts.

day wrote:According to the latest discussion on Pergers posts, it would suggest that you have created a bean that is highly soluble as we say. Perhaps it would be worth dialing it in afterall?

I will explain why I haven't tried dialing it in. The beans didn't grind like normal beans. When grinded on my HG One, the beans didn't flow out of the grinder very easily. It took probably 4 times as long to get through a 15g dose, as if my grinder had accidently slipped and was set to twice as fine. The beans felt like they were gumming up in the burrs but they weren't. They just weren't flowing out at the typical rate. The grounds seemed to be slipping between the burrs. "Hmm. That's odd," I thought.. I had a feeling it was going to result in a choked shot, but to my surprise it flowed like a faucet. In order for me to get a tight enough extraction, I'd have to adjust the grinder setting significantly finer. But that meant the grounds might never completely exit grinder. I really don't know what physically happened to the beans but I had concluded they were completely unsuitable for espresso. I verified the grinder setting remained correct by grinding and pulling a shot with normal beans right after.

I have something additional to report. Now that I've been trying them in my usual drip brews (Kalita PO) over the past couple of days, I compared them side by side with the normal drum roast. I found the quenched roast to have degraded quickly. The brew was clean on entry, however the brightness was reduced and the finish was slightly bitter.

Like the research suggested, you may have inadvertently added moisture to the bean. When I did my initial reading into quenching the guides suggested that all that was necessary was room temperature mist in order to halt the high temperature reactions.
The difference between 20C and 0C is not that great in comparison to 200C... Plus room temperature is safer and easier...

" Inadvertently added moisture".. Nope, nothing inadvertent about it. I drowned the suckers! . This was not your typical quenching process.

Actually, I had weighed out the greens for both batches exactly the same before roasting them, side by side, one after another (113.5grams/4oz ea). They were roasted with the exact same profile and timing (as I could get). One was doused and then dried in the roaster at low heat, while the other air cooled. The doused ones took a day lose the residual moisture, as I didn't want to leave them too long in the roaster, even at low heat, because I did not want to dry out the exterior of the beans. In the end double checked the moisture and dosed exactly 300 beans from each batch, and they were the same weight (virtually the same, the normal roast was heavier by 1/10th of a gram, or 1 bean).

Well that's bloody interesting, then.

weebit_nutty wrote:I will explain why I haven't tried dialing it in. The beans didn't grind like normal beans. When grinded on my HG One, the beans didn't flow out of the grinder very easily. It took probably 4 times as long to get through a 15g dose, as if my grinder had accidently slipped and was set to twice as fine. The beans felt like they were gumming up in the burrs but they weren't. They just weren't flowing out at the typical rate. The grounds seemed to be slipping between the burrs. "Hmm. That's odd," I thought.. I had a feeling it was going to result in a choked shot, but to my surprise it flowed like a faucet. In order for me to get a tight enough extraction, I'd have to adjust the grinder setting significantly finer. But that meant the grounds might never completely exit grinder. I really don't know what physically happened to the beans but I had concluded they were completely unsuitable for espresso. I verified the grinder setting remained correct by grinding and pulling a shot with normal beans right after.

I have something additional to report. Now that I've been trying them in my usual drip brews (Kalita PO) over the past couple of days, I compared them side by side with the normal drum roast. I found the quenched roast to have degraded quickly. The brew was clean on entry, however the brightness was reduced and the finish was slightly bitter.

Perhaps you altered them in some way so that they were no longer as brittle. That could potentially lead to less fines when grinding and a more Unimodal grind, which would take more turns since the grinder is doing more shearing and less crushing, and would-like they say about the ek43-require a much finer grind.

At any rate, not to be offensive, but trying to use liquid nitrogen without ever even trying to dial in your initial experiment is...well it doesn't make any sense to me. Of course now that they have degraded i suppose it doesnt really matter:)

I'm not going to dial in the first roast. If you saw how they grinded in the HG One you woudn't have bothered either. I would attempt to dial them in if I had my Forte configured with the ceramic burrs. At the time I didn't have any intention of using it for espresso. But you have me thinking. I may reconsider the dry ice. There's still lots of things I could do differently with the ice bath.