Freeze/Thaw, Freeze/Thaw, Freeze/Thaw Greens? - Page 2

Discuss roast levels and profiles for espresso, equipment for roasting coffee.
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LBIespresso
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#11: Post by LBIespresso »

mkane wrote:^^^same here but smaller batches. I've also quit buying some much.
For now, Mike...for now :lol:
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rmongiovi
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#12: Post by rmongiovi »

As anyone who has accidentally frozen lettuce which turned into mush can attest, one of the problems with freezing things containing water is that ice crystals form inside the cells and puncture the cell walls. Obviously coffee beans contain much less water than lettuce but it's still there. If there's enough that freezing the coffee beans compromises the cell wall integrity then I might expect that to have an impact on first crack. If the cell wall are already weakened perhaps first crack will occur earlier than it would with unfrozen beans. If freezing does weaken the cell walls then I'd expect repeated freeze/thaw cycles to increase the amount of damage.

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Chert
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#13: Post by Chert »

I don't freeze my greens. 2020 Atitlan honey, vac packed since arrival and stored in 20 C basement, roasted this week tastes great.

Has vacpacked without freezing been compared to with freezing in a more scientific way?
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GDM528 (original poster)
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#14: Post by GDM528 (original poster) »

rmongiovi wrote:If the cell wall are already weakened perhaps first crack will occur earlier than it would with unfrozen beans.
Unfortunately, these particular greens are essentially silent at first crack, but the moisture release curve can be a good indicator on its own. There was no significant shift in the timing in the humidity curves - which might imply there was no shift in first crack timing. If the bean structure was weakened as you describe, then I might expect water would have an easier time escaping, and more of it overall would escape - which is exactly what happened. What I don't understand, is why the post-roast weight loss was the same...

The good news here, is I gave those greens eight thermal beat-downs and only saw a small effect. I'd expect it to vary across origins, altitude, processing, etc., but overall the greens appear to be tough little buggers.

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LBIespresso
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#15: Post by LBIespresso »

Chert wrote:
Has vacpacked without freezing been compared to with freezing in a more scientific way?
I am not sure but the fact that George Howell and Passenger freeze coffee for years (Passenger has "freezer fridays" where they roast coffees at least as old as 6 years) says a lot to me. Especially when you consider the cost of running industrial sized freezers.
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JohnB.
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#16: Post by JohnB. »

I've roasted greens that have been vac packed in my freezer for 10+ years. Roasts were normal as was the 1st crack time and the roasted coffee was quite good.
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