h3yn0w wrote:Frost-free models prevent this by automatically defrosting the storage area on a regular basis. Built-in timing mechanisms shut off the cold air compressor and turn on a small heater to melt the ice crystals. Once clear of frost, the freezer turns off the heater so the cold air can keep your food items stored at a safe temperature.

I'm sorry but that isn't how a Frost Free freezer works. If it was all the food inside would spoil in short order as the temp inside the food storage area would have to rise above freezing to melt off the ice, if there was any in there. I've been monitoring the temp in our 2 frost free freezers with multiple thermometers since new (2004-2006). Temp never rises more then 5°F during a defrost cycle & I keep them set at -5°F.

The frost & ice builds up on the evopartor which is located outside of the insulated food storage area. There are heating wires under or around the evaporator which heat up during a defrost cycle & melt away the build up which drips down to the pan underneath. The cold, dry air circulating through the storage compartment keeps ice from building up & removes any frost that might appear after having the door open.

h3yn0w wrote:If we are going to look at this in a scientific way, we need to explore different ways to store the beans but also different freezers.

There are many potential variables to consider. But right now nobody is doing any sort of controlled experiment.

I would propose something very simple. Split up a bag of the same coffee beans, filling two jars. Vacuum one of them. Alternatively, put beans into a tightly rolled standard ziplock and a vacuum sealed bag. Or do all four if you have the means. Store them in the freezer for 3 months, whatever freezer you have. Then do blind tastings. Repeat the whole thing at least once preferably with a different type of coffee.

It would be easy to do. If I had a Foodsaver I'd try it.

JohnB. wrote:I'm sorry but that isn't how a Frost Free freezer works. If it was all the food inside would spoil in short order as the temp inside the food storage area would have to rise above freezing to melt off the ice, if there was any in there. I've been monitoring the temp in our 2 frost free freezers with multiple thermometers since new (2004-2006). Temp never rises more then 5°F during a defrost cycle & I keep them set at -5°F.

The frost & ice builds up on the evopartor which is located outside of the insulated food storage area. There are heating wires under or around the evaporator which heat up during a defrost cycle & melt away the build up which drips down to the pan underneath. The cold, dry air circulating through the storage compartment keeps ice from building up & removes any frost that might appear after having the door open.

It may not rise above freezing but it rises / fluctuates a certain amount and I would imagine every situation is different. Not claiming to be an expert on this but I've read some info that suggests temp can rise 20 F depending on what your set point is.

As I posted in the 10 years that I've monitored our freezers I've never seen that. The alarms would go off if it did & we'd never see the extended storage times for our garden produce & meats that we get. I have to think that some of the info out there is based on the early FF technology.

dmw010 wrote:It takes me less than 5 minutes to portion and seal a bag of coffee into jars.

Having just gotten the tools dmw010 is using, I can vouch for the idea that it is very quick and easy to vacuum seal.

Can I ask you how long you apply the pump to the jar for to get whatever degree of vacuum you're creating? With a bag, it's easy to tell how much air is in the bag. You can see and feel it. Not so with a jar, though I may be lacking some info with which I can perceive this. I'm doing about 10 seconds, but other than that it's creating a fairly tight seal, I don't know much more. I can, with a middling amount of effort, pry the lid loose with my fingers. I suppose I could do this until the seal is so tight I can barely pry it loose at all. That would indicate something, I suppose.

maigre, you can get an idea by opening an empty jar submerged upside down in a sink full of water so that water is pulled into the jar. The fraction of the jar that fills with water is a rough measure of the vacuum that you are pulling. Of course with beans in the jar you'd need to pump proportionally less. Coffee beans occupy about 2/3 of the space in a full jar so figure 1/3 as much pumping when the jar is full to achieve the same vacuum. Roughly speaking.

If the lid is vac sealed properly the center of the lid will pop in. Removing the lid should require prying up on the side with a butter knife or other tool. I use one of the freezer keys & pry up between the top jar thread & the lid. If you can pop it off with your fingers it's not a good vacuum seal.

Thanks, both Johns.

JohnB. wrote:Try it & see for yourself. I'd say it does reduce the void as the collapsed bag pulls the beans tightly together.

A friend was kind enough to loan me her Foodsaver for a little while. So I measured the void.

What I found was that in a 16oz canning jar filled with beans the void was approximately 36% of the jar volume. Using the same beans in a vacuum sealed bag it was about 25%. The vacuum sealed bag had roughly 40% less air space than the jar.

For what it's worth, these were medium roast Central American beans.
Also, this Foodsaver pulled a vacuum of 21 inHg (measured inside the bag).


Now I'll have to buy some fresh coffee and do the little experiment I mentioned previously.

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Edit (7 Feb 2017): Initial results

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