Grinding coffee beans stored in a frozen bean cellar without defrosting? - Page 2

Grinders are one of the keys to exceptional espresso. Discuss them here.
BruceWayne
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#11: Post by BruceWayne »

Frost free freezers cycle the temperature to melt the frost. Also, you want your freezer to be at least 0 F if not colder, so two likely reason you didn't get good results.

jpender

#12: Post by jpender » replying to BruceWayne »

Can you explain why you believe that would matter?

tesuji

#13: Post by tesuji »

Formation of ice crystals, and/or expansion of water due to freezing, may cause microscopic damage to cell walls, increasing oxidation and the potential for development of off flavors?

BruceWayne
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#14: Post by BruceWayne »

A frost free freezer has to raise the temperature to at least 0 C to melt the frost, so the freezer is cycling from its lowest temp to the melting point of water. When I was searching for articles on the effects of freezing on coffee, it looks like keeping coffee at liquid nitrogen temps stops bean degradation entirely, while most of the processes that degrade stored beans happen between room temp and -20 C. Keeping the beans at a constant temp below -20 C (-4 F) extends the storage time significantly.

The thermometer I bought for my freezer indicates the freezing zone starts at 0 F for storage and you'll find recommendations to keep freezers at least that temp for long term storage.

So, your freezer isn't cold enough and is constantly cycling to even warmer temperatures regularly. I keep my beans in a chest freezer that's a few degrees below 0 F and have excellent results so far.

jpender

#15: Post by jpender »

Frost free freezers don't warm up above 0°C. If they did all of your ice cream would melt.

BruceWayne wrote:The thermometer I bought for my freezer indicates the freezing zone starts at 0 F for storage and you'll find recommendations to keep freezers at least that temp for long term storage.
Your thermometer doesn't know what you're storing in your freezer. The recommendation for a temperature of 0°F or lower has to do with inhibiting microbial growth in food, something that is a non-issue with coffee.

BruceWayne wrote:So, your freezer isn't cold enough and is constantly cycling to even warmer temperatures regularly. I keep my beans in a chest freezer that's a few degrees below 0 F and have excellent results so far.
I have excellent results using a frost-free freezer. A chest freezer would be better, although not as good as something even colder. The lower the temperature, the slower the chemical reactions. If I didn't have a freezer I'd put the coffee in the refrigerator. And if I didn't have a refrigerator I'd keep coffee I'm not currently drinking down in the basement, next to the wine.

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JohnB.
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#16: Post by JohnB. »

BruceWayne wrote:A frost free freezer has to raise the temperature to at least 0 C to melt the frost, so the freezer is cycling from its lowest temp to the melting point of water. When I was searching for articles on the effects of freezing on coffee, it looks like keeping coffee at liquid nitrogen temps stops bean degradation entirely, while most of the processes that degrade stored beans happen between room temp and -20 C. Keeping the beans at a constant temp below -20 C (-4 F) extends the storage time significantly..
I have 3 frost free storage freezers & I monitor temps in all of them. They never come anywhere near 32°F in the food compartment. The actual defrosting takes place outside the food compartment on the cooling coils which have heating wires running through them. During a defrost cycle the temp in the food compartment will rise slightly (5°-8°F) but drops back to 0°F or less as soon as the cooling cycle resumes. I've stored some roasted coffees in these freezers for 6 months or longer with no really noticeable flavor loss.
LMWDP 267

pizzaman383
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#17: Post by pizzaman383 »

Rcus wrote:The temperature for pour over should be 4 degrees Celsius more to get similar results as unfrozen fresh beans.
If you aren't adjusting temperature or waiting until the beans are fully up to room temperature you can notice taste differences.
Curtis
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“Taste every shot before adding milk!”

Rcus

#18: Post by Rcus » replying to pizzaman383 »

I was using 92 degrees Celsius water to do the pour over when it's not frozen. After I freezed those beans and I tried different parameters for those frozen beans, I found that using 96 degrees Celsius water without defreezing would get a highly similar if not the same taste of coffee. If your environment is different, you may surely get different results. And my method is good for me because I can save time to weigh the beans (I did it when I repack them into small zip bags and removed bad beans at the same time. ) and the whole process of making coffee is not changed. Definitely it's not suitable for business use. I can also guarantee to get the same result among the whole period of using that beans

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JohnB.
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#19: Post by JohnB. »

pizzaman383 wrote:If you aren't adjusting temperature or waiting until the beans are fully up to room temperature you can notice taste differences.
Have you measured the difference in the prepared puck temp between the two? I just measured the bean/grounds temp on their journey from the freezer to the grouphead with an infrared temp gun. I remove a jar from a 0°F freezer & dose into a container on a scale I keep next to the freezer.

Bean temp by the time I was done dosing & walked back to the grinder = 26°F.
Grounds temp in the pf = 80°F
Temp of the puck just before lockin = 77°F

I'll take the same measurements with beans up to room temp in a couple hours & post the info. How much of a temp adjustment are you making?
LMWDP 267

pizzaman383
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#20: Post by pizzaman383 »

I can taste the difference. I adjusted my group head and brew boiler temperature up 2-3 degrees to get rid of the sourness that happened when I started freezing my beans.
Curtis
LMWDP #551
“Taste every shot before adding milk!”