Coffee Storage experiments

Want to talk espresso but not sure which forum? If so, this is the right one.
CathyWeeks
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#1: Post by CathyWeeks »

Ok, I started my experiment today. I am using the following containers:
  1. 3-ounce glass spice bottle with metal screw-top lid: http://www.containerstore.com/s/kitchen ... d=10013579
  2. 3-ounce acrylic bale-top spice jar: http://www.containerstore.com/s/kitchen ... d=10011992
  3. 125 ml bale-top Fido canning jar: http://www.amazon.com/125-Terrine-Herme ... B00DH08GRE
  4. Evak Mini valved storage: http://www.amazon.com/dp/B00UMXUG54/
  5. Resealable plastic vacuum bags: http://www.amazon.com/Waring-PVS1000CGB ... 009O9VI86/
I packed 33-grams of coffee beans roasted YESTERDAY (Peace Coffee in Minneapolis) in each kind of storage (Guatemalan light roast). I used two bags for each - one I will vacuum out any out-gassed CO2 each day until it remains a brick, and the other I will allow to remain puffed up from any outgassing that occurs. It has a valve, so shouldn't pop. I will do a cupping each week for four weeks, to see how the different kinds of storage do over time. I intend to repeat the experiment by packing on roast day+0, roast day+2, roast day +3, etc. They couldn't get me same day roasted beans this time, but with more advance notice, will be able to do that. Kind of a hassle, as the roastery is only open M-F, 8-4, during business hours, which means I have to take time off work to go get it. And it's 50 minutes from my home. Ah well, 1x per month isn't bad.

My daughter is going to mix the samples for me, so that I don't know what I'm tasting, and I will take notes. I will not look at the sample-match ups until 4 weeks are up, so that I cannot draw conclusions until the experiment is over.

I would LOVE for others to do similar experiments, and post their results here.

Oh, here's a picture:

RyanJE
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#2: Post by RyanJE »

Very cool! Do you not intend to freeze the beans?
I drink two shots before I drink two shots, then I drink two more....

CathyWeeks (original poster)
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#3: Post by CathyWeeks (original poster) replying to RyanJE »

No, I hadn't. But, since this is supposed to be a fair and blind trial, and because you reminded me of that, I vacuum-packed up 4 more samples (I had 3/4 of a bag left over) and froze them. :D

But, they didn't get packed at the same time as the others. When I picked up the coffee from the roaster yesterday afternoon, they were less than 24 hours post-roast (though not much less). I packed everything up about 7:30pm last night, and the remainder was put into an Airscape (I had about 3/4 of a bag left, from my original 3). I took the freezer samples from the Airscape, which means they were packed 11 hours after the rest of the samples. So, that's something I'll have to note as a difference. However, I'll include freezing in with my future rounds, and pack the to-be-frozen samples at the same time as the rest.

A long time ago, I decided freezing the coffee made it taste funny, so it's something I do only rarely, and have concentrated my efforts over the years at preserving them at room temperature. But the whole point of this is to see what actually works, and bypass my own pre-conceived notions.

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tohenk2
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#4: Post by tohenk2 »

CathyWeeks wrote: But the whole point of this is to see what actually works, and bypass my own pre-conceived notions.
applause

RyanJE
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#5: Post by RyanJE »

Well we look forward to the results! I personally freeze right now so am very interested myself in your thoughts about how that affects taste.

The consensus by members much more experienced than myself is that it does not affect taste and was shown not to in blind tasting.

Of course, that would all rely on a dependable seal and process, etc.
I drink two shots before I drink two shots, then I drink two more....

CathyWeeks (original poster)
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Joined: 8 years ago

#6: Post by CathyWeeks (original poster) »

Thanks. I really hope others will do similar experiments and post their results as well. A great deal of coffee-making is based on personal preference, and also I suspect, on urban legends, conjecture, and trends (I'm not finger-pointing here - I know that I'm as bad as the next person about latching onto coffee trends). That's partly why I decided to just go back to the basics, and why I'm going to do a blind cupping. (I could totally see myself thinking that the most expensive options were the obviously the best, and therefore produced the freshest beans a the time of the cupping, if I knew which was which).

I'm trying to cover 4 different storage philosophies here:
  1. Vacuum packing/removing as much O2 as possible.
  2. Airtight seals that allow pressurization from the CO2, but not so tight that O2 can't be driven out.
  3. Freezing, which would presumably halt outgassing, which I would guess means that it's better to freeze beans at the peak, about roast+3, rather than before.
  4. Valves that let CO2 out, but no air in.
If pressurization is key to preserving flavor and freshness, then I would think that the baletop containers would be best - an airtight seal, but not so tight that O2 isn't driven off, as the pressure builds. And, all of this hinges on how fresh the beans are. VERY fresh beans are going to produce lots of CO2. But beans at a roast+5 much, much less, so the storage needs would be different. Once a bean is no longer out-gassing, it cannot pressurize the container that it's in. I would hypothesize that coffees that are more than one week post roast would do better vacuum packed, or packed in an O2-free environment (flushing with CO2 first? Not sure how I'd do that).

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doublehelix
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#7: Post by doublehelix »

CO2 is denser than air---if you have a tank of CO2, simply flush a containers of beans with this gas and it will displace air. To do this, place a tube at the bottom of your container filled with beans than let the CO2 flow. If you want to see how much time you need to flush for, place a lit match near the container's opening-- it will extinguish when filled with CO2.

CathyWeeks (original poster)
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#8: Post by CathyWeeks (original poster) replying to doublehelix »

Cool, thanks.

I was thinking about getting a clear plastic bin (like for under the bed), and placing all of my ready to go containers, but with the lids off inside it, giving it a blast of CO2, and then lidding the containers while inside the bin. I'm curious how long the CO2 will be in the bin, before it disperses. I was even thinking about cutting two holes in the lid of the bin, big enough for me to fit my hands and lower arms in, to help prevent the dispersal before I completed packaging my beans.

OldNuc
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#9: Post by OldNuc »

Keep in mind that both O2 and CO2 are gasses and there is a huge space between the individual molecules. Purging is a somewhat complex process and just a blast of gas is a complete waste.

The heavier molecule gas must be fed in at the bottom at a very slow feed rate. A candle is not a valid test of zero O2. Figure 5-8 times the volume of the container of purge gas.


The other thing to consider is some of these storage mechanisms tend to markedly shorten the useful life of the coffee when removed from storage. You want the coffee to remain stable for as long as possible after removal from storage.

CathyWeeks (original poster)
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#10: Post by CathyWeeks (original poster) »

OldNuc wrote:Keep in mind that both O2 and CO2 are gasses and there is a huge space between the individual molecules. Purging is a somewhat complex process and just a blast of gas is a complete waste.
Why? Dispersal?
The heavier molecule gas must be fed in at the bottom at a very slow feed rate. A candle is not a valid test of zero O2. Figure 5-8 times the volume of the container of purge gas.
If it's heavier, why wouldn't a slow release over the top just fall to the bottom of the container? The candle isn't a valid test of zero O2, but it would test for a lower oxygen environment, yes? I guess the issue is if the candle requires a LOT of O2, then the candle test might only show that it's ever-so-slightly lower O2, rather than significantly? And why 5-8 times? (My last chemistry class was 29 years ago).
The other thing to consider is some of these storage mechanisms tend to markedly shorten the useful life of the coffee when removed from storage. You want the coffee to remain stable for as long as possible after removal from storage.
I don't think that matters, given that I'm testing single-serving batches. (It was the LWW Bean Cellar that got me interested in this.) Unless you mean that it would be such that the 10 minutes between coming out of storage, and being brewed is impacted?

Also, which ones? I know from reading here, that Illy coffee goes stale remarkably quickly once it's opened, being pressurized. But I thought it was on the order of magnitude of days, not minutes?

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