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Homeroasters.org » THE ART OF ROASTING COFFEE » Storing Roasted Beans
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storing roasted beans
ChicagoJohn
Has anyone here had personal experience with trying to vacuum seal and deep freeze roasted beans to see if there is a noticeable effect upon results in the cup? Back before I roasted myself, I tried this with roasts I picked up at our local place and it seemed to work out OK as I recall.

I was thinking about trying an experiment along these lines but if it's established technology I don't want to re-invent the wheel.
So many beans; so little time....
 
MPSAN
I ALWAYS vac seal my roasted beans using a FoodSaver and Canning Jars. However, I NEVER freeze coffee in ANY form!
"If it Ain't Broke, Fix it 'til it is"!
 
ChicagoJohn
MPSAN wrote:

I ALWAYS vac seal my roasted beans using a FoodSaver and Canning Jars. However, I NEVER freeze coffee in ANY form!


Just curious as to your rationale for this; personal experience, others' experience, a theoretical basis, etc. Obviously you feel pretty strongly about what you are doing and I'm assuming there is a reason for that.
So many beans; so little time....
 
Ringo
I always roast a lot and freeze till needed in mason jars. I think it works good but you have to let the beans warm before you open the jar. I roast in 5 pound batches so I will always have extra.
All you need in life is ignorance and confidence, and then success is sure. Mark Twain
 
JETROASTER
I will also suggest freezing with confidence. Thaw before any exposure (to prevent any condensation).
The results are impressive. Blooms like fresh roasted coffee.
Cheers, Scott
 
MPSAN
ChicagoJohn wrote:

MPSAN wrote:

I ALWAYS vac seal my roasted beans using a FoodSaver and Canning Jars. However, I NEVER freeze coffee in ANY form!


Just curious as to your rationale for this; personal experience, others' experience, a theoretical basis, etc. Obviously you feel pretty strongly about what you are doing and I'm assuming there is a reason for that.


I always had been told that Freezing beans in any form can add moisture. This is especially true when you defrost them. I had heard of someone on this forum who Vac Sealed them as I do with a Foodsaver and Mason Jars and roasting 3 year old beans.
"If it Ain't Broke, Fix it 'til it is"!
 
Ringo
I do also vac seal all my green beans and I think it helps them last longer but they do age. I try not to let anything get over a year old. I vac seal in mylar.
All you need in life is ignorance and confidence, and then success is sure. Mark Twain
 
ChicagoJohn
I really appreciate the sharing of your experience on this. Being new to this, I depend a lot on the anecdotal accounts of others. On green beans, I have been vacuum sealing a pound and storing it in a deep freeze at -5F. I always take it out and let it sit at ambient for 24 hours and then cut the bag to release the vacuum and allow it to sit in ambient humidity for a few days before roasting. So I'm with you on that.

Based on what I've read, I think I will try to construct an experiment to compare the taste difference of beans roasted and then vacuum sealed and stored in a deep freeze with green beans stored beside them and then resurrected, roasted, and ground 24 hours later. While my coffee palate is undeveloped, maybe at least I'll be able to see if I can taste a difference or not.

Based solely on chemical theory, I would think removal of oxygen in storage is a good thing, and that other things being equal, reduction in temperature would be helpful in terms of reaction kinetics, assuming, of course, that the process of reacquainting the beans to ambient conditions is done in a way that does not promote condensation and that it allows enough time for them to reach an equilibrium with respect to ambient humidity.

I'll let you know my observations. And thanks again for the comments.
So many beans; so little time....
 
JETROASTER
You wouldn't have a mass spectrometer handy by chance? I look forward to your findings! Thanks, Scott
 
ChicagoJohn
JETROASTER wrote:

You wouldn't have a mass spectrometer handy by chance? I look forward to your findings! Thanks, Scott


When I was still working, I had access to one and a number of other instruments as well. But alas, nevermore, quoth the Raven.

So my experiment, flawed as it is, will be as follows:

I've purchased 2 lb of a Yirga Cheffe green been lot from my local roaster, "FreshGround Roasting" in Geneva, IL. I will mix this to insure homogeneity, but it will be coming from one bag there and that bag has never been vacuum sealed or frozen.

I am dividing this 907 gm quantity into two three-batch 91 gm charges (273 gm each), with the remainder being 361 gm, and that 361 gm will be vacuum sealed in a bag and placed in deep-freeze conditions at -5F.

All of the six 91 gm batch samples will be roasted, three on each of two successive days, using my standard roast profile which will be recorded for each batch. The product from these six batches will be thoroughly mixed to achieve homogeneity and then divided up into two equal quantities of approximately 230 gm each, yield being approximately 85% based upon charge weight.

One of the 230 gm quantities will be vacuum sealed and placed in the deep-freeze with the green beans. I will grind and drink the other 230 gm daily using my standard Aeropress method with 33 gm / 12 oz water for approximately one week, recording fragrance, aroma, and taste notes each day.

After a period of 5-6 months, assuming I am still alive and capable of continuing this experiment, I will remove the frozen green beans and the frozen roasted beans, allow them to thaw out for 24 hours, open the packages, and allow them to equilibrate for 24 hours.

I will then proceed to roast the green beans, 361 gm, in four roasts using the same profile I used previously. This should produce 307 gm of roasted beans.

After waiting a period of 48 hours, I will then alternate back and forth between the newly roasted beans and the thawed out roasted beans, attempting to document my observations regarding fragrance, aroma, and taste as best I can referencing the results I recorded six months earlier.

While I realize this experimental design is seriously flawed, I think it should be good enough for my purposes in deciding whether or not to vacuum seal and deep freeze roasted beans, or even green beans for that matter.

I've ordered beans and should complete the roasts by this coming Sunday. Be sure and check back in five to six months.

If you have any thoughts on refining the experimental design, please do it quickly.
So many beans; so little time....
 
ChicagoJohn
OK, not hearing any suggestions contrary to my plan, the roasting process for the six batches will take place tomorrow and Sunday, three 91 gm batches per day. Probably the last nice weather we'll have here in Chicagoland for a while; but who knows?

I'll of course record the roast profiles for each of the six. Then I will blend them together and allow them to stand until Wednesday so as not to interfere with any after-roast maturation processes, and then I'll vacuum-seal and deep-freeze half, along with the remaining green beans in a separate bag, and begin consuming the other half, which should take me seven days to do, documenting my unfortunately uneducated observations each day.

Then we wait until mid-May to finish it up. Any other ideas; please let me know by tomorrow morning.
So many beans; so little time....
 
allenb
Great post John and looking forward to the results of the tests. It will be nice to see an experiment of this kind done without having to read the results within 100 pages of text to get to the good stuff.

Your process/procedures look like they will provide all we could ask for.

Allen
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
JETROASTER
John,
Your diligence is greatly appreciated. When your work is done, I will do what I can to spread the word. The internet is littered with anecdotal nonsense.
I will never under-estimate the influence of home-roasters/baristas. It wasn't so long ago that a couple home grown coffee geeks put the first PID on an espresso machine.... and changed the industry.
Cheers to you Sir. -Scott
 
LongLeafSoaps
ChicagoJohn wrote:

After a period of 5-6 months, assuming I am still alive and capable of continuing this experiment...


BwaHaHaHaHA!!! Roflmao Roflmao Roflmao

Good thing I wasn't taking a drink when I read this!
Carpe Diem With Coffee
 
LongLeafSoaps
ChicagoJohn wrote:

OK, not hearing any suggestions contrary to my plan, the roasting process for the six batches will take place tomorrow and Sunday, three 91 gm batches per day. Probably the last nice weather we'll have here in Chicagoland for a while; but who knows?

I'll of course record the roast profiles for each of the six. Then I will blend them together and allow them to stand until Wednesday so as not to interfere with any after-roast maturation processes, and then I'll vacuum-seal and deep-freeze half, along with the remaining green beans in a separate bag, and begin consuming the other half, which should take me seven days to do, documenting my unfortunately uneducated observations each day.

Then we wait until mid-May to finish it up. Any other ideas; please let me know by tomorrow morning.


Interested to read your findings (assuming I am still alive also ;D )
Carpe Diem With Coffee
 
ChicagoJohn
Good thing I wasn't taking a drink when I read this!


Nothing worse than hot coffee coming out ones nose; assuming, that is, you were referring to coffee ;)

Anyway, the six 91 gm batches have been completed and the profiles are attached. As the best lay'd schemes o' mice and men gang oft agley, the first batch on each day (cold equipment and a cold, rather windy day) were outliers from the other four batches. So what is being evaluated here is actually a blend. But that possibility was taken into account in the experimental design as these six batches will be thoroughly blended before dividing the aggregate in two; the part that will be vacuum sealed and deep frozen along with a second package of the remaining green beans, and the other portion which I will drink with anecdotal notes using a record form that I have yet to devise. I think I will split up the consumption into two sections; 3 - 6 days and 7 - 10 days after roasting. The same will be done in six months with the stored roasted beans and the newly roasted stored green beans.

The overall yield was 87%, and I would consider this a med-light roast in that 1C occurred for each roast at 191C/376F. and final temperatures at around 206C/403F with variation in development time.

The batch profiles are attached.
ChicagoJohn attached the following image:
bean-storage-study.jpg

So many beans; so little time....
 
Tarhead
Thanks for doing this!
I've always wondered what freezing roasted coffee did to it but never compared the same coffee.
 
David
AFAIK, the Conventional Wisdom is:

1) Oxygen and moisture are the enemies of roasted beans.
2) Vacuum-sealed beans can be frozen for at least six moths without noticeable staling, but not forever...
3) Because the roasted beans contain enough available oxygen internally to become stale, even with the best vacuum sealing.
"Ya can't save the beans from themselves."

In keeping with that, when I freeze a pound of roasted coffee beans, I subdivide it into sealed 2oz bags or baggies. Then, those all go into a larger valved, ziplock bag. That way, when I want to make a french-press worth of brew, I just take out one of the 2oz bags. Then I quickly reseal the large bag, draw the air out of it and put it right back into the freezer as quickly as I can.
I don't worry about thawing out the 2oz of beans as their life expectancy is so very short. Shock
Just grind, brew and enjoy.

Additionally, having several packets allows me a comparison of the taste of the coffee at different intervals. That's not as good as side-by-side when tasting for nuances, but I think I can tell when they start to become stale and/or "flat."
 
ChicagoJohn
Additionally, having several packets allows me a comparison of the taste of the coffee at different intervals. That's not as good as side-by-side when tasting for nuances, but I think I can tell when they start to become stale and/or "flat."


I really like your interest in experimentation, David, since it is completely congruent with my interests; the separate packets would certainly be conducive to that.

The conventional wisdom you cited will likely turn out to be verified in my experiment, but we'll see what happens. Oxygen, more so than moisture, would be the main problem in a vacuum-seal deep freeze scenario. A temperature of -21C (-5F) is still hot compared to absolute zero (-273.15C) where kinetic energy for chemical reactions is essentially zero. My deep freeze is around 252Kelvin or 455F above absolute zero.

Since temperature is only the measure of average energy, at any given temperature, there are a wide range of molecular collision energies, some of which are sufficient to cause chemical reactions to occur. It's just a matter of the rate at which this happens (with that rate becoming zero as at absolute zero.) These phenomena are stochastic. So as our best commercial vacuum sealing machines will leave some residual oxygen, as you said, some reaction will occur over time even at -5C. If we were to put the beans in a flushed nitrogen atmosphere (or carbon dioxide) to remove virtually all the oxygen first, then longer storage potential could be achieved at any given temperature, but there can be many other non-oxidative reactions also.

From a pragmatic perspective, my interest is storing greens for around six months before roasting, and storing roasts for at most six months before grinding and brewing. I'm fully expecting the conventional wisdom you cite to be consistent with my experiment. Even this far, though, I can see there is much more variation in the day-to-day taste ratings for the same fresh roast than I'd expected. So sometimes I guess we can learn things we didn't expect to learn from our experiments :)
Edited by ChicagoJohn on 11-23-2015 08:31
So many beans; so little time....
 
Ringo
The difference between cups of the same roast is called uniformity and is one of the criteria used when cupping coffee. When I took a cupping class we would have 5 cups of the same coffee on the table every time. You would ignore the outliers, and score how uniform the others are. I have a bad pallet but can pick up some differences.
All you need in life is ignorance and confidence, and then success is sure. Mark Twain
 
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