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storing roasted beans
alext
Top  #26 Print Post
Posted on 05/26/2016 8:18 PM
Great experiment and thanks for sharing it. Since there are 2 factors involved, vacuum sealing and freezing I wonder how much one or the other contributes.
 
ChicagoJohn
Top  #27 Print Post
Posted on 05/28/2016 10:29 AM

Quote

alext wrote:

Great experiment and thanks for sharing it. Since there are 2 factors involved, vacuum sealing and freezing I wonder how much one or the other contributes.


Good question, and there are many others that could be pursued; effects of type of storage container, materials of construction, vacuum vs air vs nitrogen or carbon dioxide, storage temperature, interaction of storage temperature and the previous parameter values, and so on.

My interest, however, is in solving a practical problem; that being how to get through extended periods of time when it is impractical for me to roast due to inclement weather conditions -- primary in the winter months. From my background as a chemist, I thought it reasonable to assume that reducing temperature would favorably affect chemical reaction rates; a rule of thumb for 1st order reaction kinetics is a doubling of rate for every 10C increase in temperature, so going from 23C down to -4C might slow any reactions to about 1/7 of what they would be at room temperature.

At the same time, reactant concentrations also affect rates, so reducing oxygen availability by vacuum, should be advantageous - flushing with nitrogen or carbon dioxide even better, but I didn't have that option. In a freezer situation where there is sufficient head apace in the container, ice crystals can vaporize (sublime) and condense on container surfaces, a phenomenon that is often evident when opening packages of vegetables that have been a freezer for a long time. So minimizing air space by drawing a vacuum should be helpful in minimizing this effect as well.

So my objective was to see if this combination of storage conditions would provide a way to solve this problem I have of winter weather here in Chicagoland given my admittedly undeveloped palate when it comes to coffee. (But since I am the only consumer of the product, my perception is the sole criterion.)

Having just finished the stored beans I roasted over six months ago, right after a month's daily consumption of freshly roasted beans of the same variety, I could detect no difference at all, even though I did see evidence of some out-gassing in the roasted bean pouch during storage. I just roasted the green beans today, and would expect to see no differences there either since I followed the same roasting protocol, But if I do, I'll report it here. Otherwise I consider this a success and plan to roast enough late this year to last me through the winter.
So many beans; so little time....
 
alext
Top  #28 Print Post
Posted on 05/28/2016 10:52 AM
I have a similar need. Since I roast outside, even in the mild northern california climate there are still winter days where its too rainy (if we are lucky) or a little too cold, so having an emergency supply stored is very appealing. I have limited freezer space so I wonder how long I can get away with storing at room temperature but vacuum packing. I might have to try it out. Put one bag in the freezer and one in a cabinet.

Thanks again for sharing your experiment and comments.
 
ChicagoJohn
Top  #29 Print Post
Posted on 05/29/2016 5:56 PM

Quote

alext wrote:

I have a similar need. Since I roast outside, even in the mild northern california climate there are still winter days where its too rainy (if we are lucky) or a little too cold, so having an emergency supply stored is very appealing. I have limited freezer space so I wonder how long I can get away with storing at room temperature but vacuum packing. I might have to try it out. Put one bag in the freezer and one in a cabinet.

Thanks again for sharing your experiment and comments.


Applying the rule-of-thumb dependence of reaction rate on temperature, I was unable to detect any difference at all in the roasted beans after six months at -4F (-20C) A typical refrigerator is around 40F which is about 4C.

So if you were to store the same type of Foodsaver vacuum seal bag of roasted beans refrigerator instead of the freezer, assuming a 23C (73F) average ambient temperature, then whereas in my freezer reaction rates wee would have been slowed down to 1/16 what it would have been at ambient, in a refrigerator it would still be slowed down to 1/4 what it would be at room temperature. This assumes, again, that the various reactions follow the rule-of-thumb model.

In other words, in a refrigerator after about six weeks would yield the same result as a deep freeze after six months insofar as any chemical reactions that might occur and which follow the model are concerned.

As you point out, however, we don't know the relative contributions of temperature and of minimizing oxygen and head space. The experiment you outlined would perhaps shed some light on that, and I would look forward to hearing your results. If a six week storage interval is good enough to resolve your weather problem, then perhaps you could simply use your refrigerator which may have more available space.

I would also be interested to learn whether your roasted beans outgas like mine did even though I allowed them to stand for a considerable time (I can't recall now exactly what that was but I may have recorded it earlier in this thread). They were free flowing in the sealed bag while the green beans were a solid brick just like when I put them in. I've heard they give off carbon dioxide, but whatever the gas is, it's not oxygen and not going to react chemically with the beans since they expelled it.

I hope you learn that the vacuum sealing is sufficient alone. That would make things a lot easier.
Edited by ChicagoJohn on 05/29/2016 6:06 PM
So many beans; so little time....
 
alext
Top  #30 Print Post
Posted on 05/29/2016 7:37 PM
I just roasted today and also played around with the vacuum packer. Its the Frisper system and its ok. It doesn't use bag space that efficiently but the bags are reusable, so I guess its decent.

For the test, I will leave the roasted beans out 24 hours and then vacuum pack them. 1 bag in the fridge and one in a drawer at room temp. In 6 weeks I'll compare. Does that sound like about the right experiment?

Added: One thing I just thought of - before and after weights. This could be a good clue about moisture changes assuming precise enough scale.
Edited by alext on 05/29/2016 7:48 PM
 
ChicagoJohn
Top  #31 Print Post
Posted on 05/30/2016 5:58 AM

Quote

alext wrote:

I just roasted today and also played around with the vacuum packer. Its the Frisper system and its ok. It doesn't use bag space that efficiently but the bags are reusable, so I guess its decent.

For the test, I will leave the roasted beans out 24 hours and then vacuum pack them. 1 bag in the fridge and one in a drawer at room temp. In 6 weeks I'll compare. Does that sound like about the right experiment?

Added: One thing I just thought of - before and after weights. This could be a good clue about moisture changes assuming precise enough scale.


Before and after weights is an excellent idea -- wish I'd thought of that. When you reweigh the bags, make sure they have been out several hours so they have returned to ambient temperature -- weighing something hotter or colder than ambient can create convection currents in the air that affect the scale readings.

In my experience, it takes several days up to a week for roasted beans to sort of level off. I can definitely discern changes in flavor from 24 hours to a week. You might want to wait several days after roasting so that anything ordinarily happening in this interval doesn't interact with differences in storage temperature. I think I let my roasted beans sit for a week and then mixed them up before bagging and sealing.

Also, you might want to set the time at whatever time interval you think would work for your weather situation -- maybe two months, if you think you could get through your cold, rainy weather in that time, or even a bit longer. What we don't know is if, in my experiment, the roasted beans would still have been good at two years. So if you extend yours beyond what is pretty certain to be good in the fridge, say 2-3 months and everything is still good, then that would answer our questions regarding the practical issue of how to circumvent inclement weather.

Finally, I'll be great to see what results you get with different bags and a different vacuum sealing system. That will help us understand how important, if at all, that aspect may be.

I think it's great that you're interested in doing this, and I'm really looking forward to your results. It would be so much more convenient if this only required vacuum packing or at least vacuum packing and refrigerator storage versus a deep freeze.

PS - remember to allow beans to stand overnight at ambient after removing from any cold environment before breaking the seal to prevent moisture from the air from condensing on them.
So many beans; so little time....
 
alext
Top  #32 Print Post
Posted on 06/04/2016 6:07 PM
Welp for better or worse, I sealed the bags after 24 hours (5/30) of sitting in an open bag. Part of that was simply practical reasons but its also the point that I would prefer to keep the beans at.

I sealed 4 bags and put 2 in a drawer at room temp and 2 in the refrigerator. I decided to do 4 bags, so that I could try them at 6 week and then some later point. 60g of roasted beans in each.

Interesting thing, after 24 hours, 5/31:

Bag 1 (room temp): Brick, just like after vacuum packing.
Bag 2 (room temp): Some inflation. Not enough the beans can move but its soft and not brick like. Seems to be perfectly sealed.
Bag 3 (refrigerator): Brick, just like after vacuum packing.
Bag 4 (refrigerator): Some inflation! Nearly identical to bag 2.

The inflation in both bags seems to be around the bean mass and not the seals, so I am not sure what to say. I will continue to monitor.
 
alext
Top  #33 Print Post
Posted on 06/17/2016 10:41 AM
Update: 6/17
Start date: 5/30
4 bags vacuum packed after 24 hours rest, 60g of roasted beans in each

Bag 1 (room temp): Soft brick, not flowing. Slight change from last check.
Bag 2 (room temp): Some inflation. Beans now can move freely. Slight change from last check.
Bag 3 (refrigerator): Brick, just like after vacuum packing. No change from last check.
Bag 4 (refrigerator): Some inflation! Not as much as bag 2 above. No change from last check.

Its clear off-gassing is happening faster with the room temp bags. Curious to see variation between bags in each environment - not sure if its the beans of the bags. Once I hit about 6 weeks, I'll be opening all 4 bags and comparing to see if there are differences. That will be a high caffeination day smile
 
snwcmpr
Top  #34 Print Post
Posted on 06/17/2016 12:05 PM
I am going to make a guess.
The vacuum is not required. The off-gassing will not noticeably alter the taste. That the effects of oxygen (room air) would make a much more noticeable taste difference.
This is much like storing in a container with a one-way valve. Room air is pushed out by the off-gassing.

Another comparison might be a one-way valved container vs the vacuum. Would the vacuum withdraw more flavor, by pulling the gas out, than the canister, which would have a neutral pressure effect on the beans.

I vacuum seal for vacations, and I always have loose beans in the bags, some even after a week of so.

Ken in NC
--------------
Backwoods Roaster
"I wish I could taste as well as I wish I could roast."

As Abraham Lincoln said "Do not trust everything you read on the internet".
 
ChicagoJohn
Top  #35 Print Post
Posted on 06/19/2016 7:40 AM
I'm sure that's right. My green beans remained a solid brick and the roasted ones were loose due to outgasing even after allowing them to stand a week before vacuum sealing. The gases that come off would not include oxygen, as you said, and that is what is reactive.

As for the effect of temperature, I store roasted beans in bags with one-way valves, but I do notice changes with age. To the extent that non-oxygen related reactions occur over time, lower temperatures would be beneficial in slowing their rates. The longer-term outgasing could be due to volatilizing of low molecular weight compounds trapped inside the bean and/or the products of continuing chemical reactions.

This Fall I plan to roast, seal and freeze 15 lb to last me from December until March. I will store at least one pound at ambient temperature, try that at the end, and see whether there is any noticeable difference (to my uneducated palate, anyway smile That may help to answer the question of whether reduction in storage temperature is a meaningful factor.
Edited by JackH on 06/26/2016 5:52 AM
So many beans; so little time....
 
alext
Top  #36 Print Post
Posted on 06/19/2016 11:30 AM
Well the bags in the store even from the quality local brands never taste fresh to me. I assume they are simply relying on off gassing.

Do any commercial offerings use nitrogen? If nitrogen is cheap enough for chips I can't see why it couldn't be used for coffee as well. Unless of course it doesn't help...
 
ChicagoJohn
Top  #37 Print Post
Posted on 06/23/2016 1:12 PM
Good idea, and actually I believe nitrogen flushing has been used with coffee for this purpose. Any gas that replaces oxygen, such as nitrogen or carbon dioxide, would be beneficial in reducing oxidation rates. But there are two issues; one is ensuring that the interstitial void volume, not just the container head space, is flushed, and another is permeability of the packaging material to oxygen. Most polymers are subject to oxygen permeation via molecular diffusion and/or pinholes and other "leaks". So a thick layer or a continuous metal foil layer might be necessary. But achieving an optimum result could be costly in relation to the competitively pricing the coffee.
Edited by JackH on 06/26/2016 5:51 AM
So many beans; so little time....
 
gadget
Top  #38 Print Post
Posted on 06/23/2016 3:00 PM
Illy does package its coffee with presurizes nitrogen. They patented it so thats probably why other coffee brands cannot do this.

http://www.illy.c.../packaging
Edited by JETROASTER on 06/23/2016 4:08 PM
 
ChicagoJohn
Top  #39 Print Post
Posted on 06/25/2016 3:00 PM
It is interesting that a patent was issued for this because it is a method that is commonly used in storage situations where the presence of oxygen is detrimental. Unless the patent has other unique claims, such as a particular package design or sealing method, I would have thought the mere use of nitrogen or other relatively inert gas, such as carbon dioxide, would have been considered to be obvious and/or prior art and thus not patent-worthy. But these days the US Patent Office is happy to take applicants' money and often issue patents which are subsequently not upheld in court when an infringement suit is filed.
Edited by JackH on 06/26/2016 5:50 AM
So many beans; so little time....
 
gadget
Top  #40 Print Post
Posted on 06/26/2016 1:21 AM
I found this patent and it is very specific to coffee beans. It describes their complete process from after the beans are roasted until they are canned...

http://patents.ju...nt/4748030
Edited by JackH on 06/26/2016 5:50 AM
 
ChicagoJohn
Top  #41 Print Post
Posted on 06/27/2016 9:53 AM

Quote

gadget wrote:

I found this patent and it is very specific to coffee beans. It describes their complete process from after the beans are roasted until they are canned...

http://patents.ju...nt/4748030


Thanks for providing a link to the patent. I read the claims and the process they describe is interesting. In order to qualify as infringement, all of the claims of a patent must be utilized. If a process for aging roasted coffee does not utilize every claim cited in this patent, then it would not qualify as infringement. For example, claim 5 specifies periodic measurement. So if a process were to essentially follow the process as outlined and not include periodic measurements, it would not constitute infringement. In my reading of it, it would not apply to flushing with a non-reactive gas in packaging.

Sometimes companies seek patents simply to be able to say in their advertising something like "We use a patented process in aging our roast" but my impression in reading these claims is that they probably did considerable empirical research in developing the process they describe. From my personal experience, and that of others I've read, there are definite changes in the cup which occur upon aging after completion of a roast, and I'm not surprised that changes in ambient temperature, humidity, and composition of the gaseous environment can impact that.

Thanks again for the link.
So many beans; so little time....
 
alext
Top  #42 Print Post
Posted on 07/11/2016 4:00 PM
Update: 7/11
Start date: 5/30

Due to coffee emergency I ended up opening and trying Bag 2 - which was the one stored at room temp and the bag had some inflation. It was not bad but had an obvious loss in quality. I can't be sure if the inflation was due to off-gassing or leakage. Its curious that Bag 1 in similar conditions did not inflate...

Here is the update on the rest:

Bag 1 (room temp): Soft brick, not flowing. No change.
Bag 2 (room temp): n/a
Bag 3 (refrigerator): Brick, just like after vacuum packing. No change.
Bag 4 (refrigerator): Some inflation! Not as much as bag 2 above. No change.

Week 6 will be this weekend and I am curious to see if the refrigerated one is ok or not.
 
HoldTheOnions
Top  #43 Print Post
Posted on 07/11/2016 5:29 PM
I bought these bags https://www.amazo...&psc=1 and I have been using for a while, I can say with certainty that the coffee tastes better to me after being out of the bags and in the hopper for a couple days, no matter how long the beans have rested in the bags. I don't know what that means. I do squeeze the extra air out of them before zipping. Wondered if anyone else experienced the same.
 
ChicagoJohn
Top  #44 Print Post
Posted on 07/12/2016 6:23 AM

Quote

HoldTheOnions wrote:

I bought these bags https://www.amazo...&psc=1 and I have been using for a while, I can say with certainty that the coffee tastes better to me after being out of the bags and in the hopper for a couple days, no matter how long the beans have rested in the bags. I don't know what that means. I do squeeze the extra air out of them before zipping. Wondered if anyone else experienced the same.


I took a look at these bags on Amazon just now, and I didn't see anything regarding the materials of construction. Are they foil-lined or do they use some sort of plastic?

Your post suggests that you've experimented with the variable of aging time after roasting and have ruled that out. I think many people notice that resting the roasted beans for several days improves them, but the changes involved should happen regardless of the ambient gas.

Could the bags be imparting some taste and flavor to the beans being stored in them which dissipates upon subsequent storage in your hopper? Or maybe there is something beneficial happening with respect to your preferences by storing the beans in air with oxygen versus an oxygen depleted environment? Maybe you could see if you get the same effect in, say, a plain aluminum foil pouch. If you do, that would favor the second hypothesis, and if not, the first.

I've never tried these particular bags. I am re-using the foil-lined one-way valve bags I obtained from coffee purchases at my local roaster, and I've not experienced what you are reporting with them, only the beneficial effect of resting for several days after roasting.
So many beans; so little time....
 
alext
Top  #45 Print Post
Posted on 07/18/2016 4:50 PM
My scientific rigor may be lacking but I believe I have some results smile

I opened the bag from the fridge that had no inflation and tried it. According to my questionably accurate scale, there was no weight change. The coffee tasted good. I do believe that there was a slight change from fresh roasted, pre-stored but taste memory isn't perfect for sure. No question that is tasted better than bag #2 noted above (inflated bag stored at room temp).

I still need to try the remaining bag to complete my test but within the limits of this experiment I can say refrigeration is better despite vacumn packing. I'll update if I find inconsistent results with the remaining bags.
 
HoldTheOnions
Top  #46 Print Post
Posted on 07/18/2016 5:12 PM

Quote

ChicagoJohn wrote:

Quote

HoldTheOnions wrote:

I bought these bags https://www.amazo...&psc=1 and I have been using for a while, I can say with certainty that the coffee tastes better to me after being out of the bags and in the hopper for a couple days, no matter how long the beans have rested in the bags. I don't know what that means. I do squeeze the extra air out of them before zipping. Wondered if anyone else experienced the same.


I took a look at these bags on Amazon just now, and I didn't see anything regarding the materials of construction. Are they foil-lined or do they use some sort of plastic?

Your post suggests that you've experimented with the variable of aging time after roasting and have ruled that out. I think many people notice that resting the roasted beans for several days improves them, but the changes involved should happen regardless of the ambient gas.

Could the bags be imparting some taste and flavor to the beans being stored in them which dissipates upon subsequent storage in your hopper? Or maybe there is something beneficial happening with respect to your preferences by storing the beans in air with oxygen versus an oxygen depleted environment? Maybe you could see if you get the same effect in, say, a plain aluminum foil pouch. If you do, that would favor the second hypothesis, and if not, the first.

I've never tried these particular bags. I am re-using the foil-lined one-way valve bags I obtained from coffee purchases at my local roaster, and I've not experienced what you are reporting with them, only the beneficial effect of resting for several days after roasting.


They are totally plastic. I might think the valves didn't work, but the bags don't blow up and air comes out if I squeeze them, so seem ok. I'm kinda rethinking this now, maybe I just like aged beans better, so they are tasting better to me after I first drink them regardless of where they are, and a few days in hopper isn't enough for noticeable oxidation to set in? Thinking now prolly more like that then the bags themselves. Also thinking maybe I should try longer rest periods, e.g. 14 days and see how I like that. Hmmm.
 
HoldTheOnions
Top  #47 Print Post
Posted on 07/18/2016 5:14 PM

Quote

alext wrote:

My scientific rigor may be lacking but I believe I have some results smile

I opened the bag from the fridge that had no inflation and tried it. According to my questionably accurate scale, there was no weight change. The coffee tasted good. I do believe that there was a slight change from fresh roasted, pre-stored but taste memory isn't perfect for sure. No question that is tasted better than bag #2 noted above (inflated bag stored at room temp).

I still need to try the remaining bag to complete my test but within the limits of this experiment I can say refrigeration is better despite vacumn packing. I'll update if I find inconsistent results with the remaining bags.


My only thought is the effect on moisture may be different for different people depending on where you live?
 
ChicagoJohn
Top  #48 Print Post
Posted on 07/19/2016 11:31 AM

Quote


They are totally plastic. I might think the valves didn't work, but the bags don't blow up and air comes out if I squeeze them, so seem ok. I'm kinda rethinking this now, maybe I just like aged beans better, so they are tasting better to me after I first drink them regardless of where they are, and a few days in hopper isn't enough for noticeable oxidation to set in? Thinking now prolly more like that then the bags themselves. Also thinking maybe I should try longer rest periods, e.g. 14 days and see how I like that. Hmmm.


You're doing basically what I've been doing -- trying different things to see what the effects are. There are so many potential intervening variables (like Hold the Onions alluded to in mentioning moisture, for example or other parameters with values unique to ones own situation) that it's probably best to start out with advice from others and then try things from there. Sort of like in cooking where you might start with a recipe given to you but then experiment with variations. And what works for one person may not be the best thing for someone else.

Although I've only been doing this for a short time, I will say that I've pretty much succeeded in my original goal of having a good cup of coffee each morning that is repeatable; beans, roasting profile, and preparation. So we'll see if the storage thing works for me this coming winter.

The negative part is that I can no longer tolerate a cup from places I used to go when traveling. The times I've tried, I wind up dumping it after a few sips. The only exception was once on the toll road I stopped at a Starbucks and discovered they had a light roast pour-over. I found I was able to drink that. But everything else I've tried is just disgusting. Luckily I don't travel that much anymore since I retired.

Good luck and please continue to report your experiments and results with storage methods.
So many beans; so little time....
 
RA5040
Top  #49 Print Post
Posted on 06/29/2018 7:13 AM
Very interesting post ... thanks!

I'm new to roasting and have only just started trying vacuum bags for short-term storage (a few weeks).

I came across this PhD thesis which is really worth looking at:

https://atrium.li...e=2#page68

It has to do with the effect of temperature and humidity on CO2 outgassing. Here are some useful snippets of information:
- 1gm of roasted coffee will eventually release a total of about 10mg C02 (about 5ml at 25C, or 3ml at 3C)
- temperature has a significant effect on outgassing rate: total degassing goes from 800 hours at 25C to 1600 hours at 15C. There is no figure for total degassing at 4C, but extrapolating roughly it's probably in the order of 3000 hours, or 4 months.
- Relative humidity has a much greater effect. At 81% and 25C, degassing is complete within 100hours, whereas at 58% the beans are still degassing after 1200 hours.

There are no figures for freezer temperatures unfortunately.

I would welcome some scientific input here, but in the meantime, here is what I think/hope/guess:
- outgassing is a feature of staling, so slowing it down should help
- If the pressure in the bag is 0.5atm, say, then the RH should be half of what it is at atmospheric pressure (with no temperature change): so vacuum-sealing should in itself help to slow down outgassing (and so possibly staling).
- If the temperature is decreased then the relative humidity will go up. So it may not be a good idea to store the bag in the fridge, whereas it may be fine in the freezer as the water vapour should crystallize out. This would also make me think that it might be a good idea to warm up the beans fairly quickly, at room temperature and with the bag opened rather than in the fridge with a closed bag.
- If what I'm saying here is true (I would be so lucky!) then outgassing in the freezer should be very slow - however it won't be zero, so it would be important to make sure that there is some elbow room in the bag.
- Storing the beans vacuum-packed at room temperature should be better than not vacuum-packed ... however, a bag with plenty of spare space would need to be used if the beans are to be stored for any length of time.
- Putting a bag of food grade silica gel should make things a lot better ... and might make room temperature storage in vacuum bags a viable option.
- filling the bag before sealing with carbon dioxide or nitrogen should also be very effective (I'm thinking of a tyre inflator with C02 cartridges as a cheap and compact solution).
- It may be a good idea to vacuum pack the beans soon after roasting to reduce the intake of moisture.

So plenty of things to try out -smile

In my VERY limited trials so far I've found that out of 8 vacuum-packed bags, one appeared to have degassed while the others had not (after a few days). I put the bag under water and by squeezing it as well as I could I found that there was a very small hole at one seam ... so nice intake of oxygen and humidity there!

Cheers

Robert
Edited by JackH on 06/29/2018 3:36 PM
 
jonuk vietal
Top  #50 Print Post
Posted on 08/02/2019 5:47 AM

Quote

ChicagoJohn wrote:

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.


ive tried it, it works good! no loss in taste until you get some moisture inside, even f it freees, as soon as you defrost it it makes the bean tatse paler somewhat
Be the best you you can
 
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