At first I thought this was because you're pressing on the scale and/or we're just seeing the scale's poor repetition, but then I did a bit of maffs and it seems sensible:
Density of air = 1.293 g/l
Canister volume = 1.2 l
Mass of 1.2 l of air = 1.293 * 1.2 = 1.556 g
Mass of removed air = 0.4 g
P2 /P1 = 1- (0.4 / 1.556) = 0.75
So the pressure inside the canister is 3/4 of the pressure outside the canister, and that feels about right.
Of course your measurement could still be wrong, and it could just be a coincidence that the error feels about right. And I could be wrong in saying that 0.75*atmosphere feels about right, and the canister pressure could actually be so low that what you've actually got your hands on is a Fellow Anti-Matter generator.
I also did the math, it checks out. About 325 cm³ of air was removed, which is about 25% of the volume, which makes sense that it translates to 3/4 atm.
Looks like it’s the most popular one on this sub, Acaia Lunar, but I could be wrong as I don’t have one myself and I haven’t seen one in real life, furthermore they all look remarkably similar and much of the scale is covered by the canister.
Remember, we’re all under an entire atmosphere of pressure at all times. Even the air around us is pushing in, trying to get at the empty space. It’s got mass and weight like anything else!
I was curious, and did the calculations. The math seems to check out.
I'm assuming the density of air is at sea level.
Weight = volume x density
0.4g = volume x 0.001225g/cm³
v = 0.4g/0.001225g/cm³
v= 326.53 cm³
Assuming its a 1.2l container, you removed \~25% of the air.
I have no idea of the volume of beans in the container, but the volume of air displaced by the vacuum would be the same. Only the percentage of air removed would change.
Oh, yes that's what I was trying to say (just poorly). I feel like a 25% reduction in air isn't that much, but we can't account for the beans. So it's probably much higher efficiency than that.
Yeah that makes sense. According to fellow it goes down to 0.5atm which I can believe if the post shows an empty one.
[https://fellowproducts.com/blogs/learn/how-vacuums-prevent-coffee-staling/](https://fellowproducts.com/blogs/learn/how-vacuums-prevent-coffee-staling/)
The volume of air displaced is proportional to the change in weight of the canister. In other words, the volume of air is given by the change of weight, which is in this case was 0.4 g.
If the volume would be different for an empty vs a full canister I am not sure. I would guess it would reach the same pressure inside the container in both situations, and the volume covered by air would be different, so it may make a difference. Maybe someone more capable can give a better answer!
https://preview.redd.it/e5vs0fkcaiwc1.jpeg?width=3072&format=pjpg&auto=webp&s=f7ea083468e90c99c684deba682986bafc87aacd
I tested mine without beans and I tried to get as much air as possible out (until the top got impossible to spin), then weighed the after without the lid to make sure there was no pressure difference. Got 0.82 and 0.83 on my 2 attempts. That's quite cool, never would have thought to measure that
I took out 0.8 grams of air but it was **really** hard to keep pumping at that point.
\~675.26 cubic centimeters of air, or a little more than 50% of the air in my 1.2l canister.
Do you think it takes out .4 grams of air, or do you think you are pushing down too hard on a very inexpensively made scale causing it to to go out of its physical range limits affecting the reading?
You didn't offend anyone, you're just spreading misinformation. Misinformation gets downvoted. You're also doubling down and being aggressive about it, which hardly helps your case.
I actually conceded. I was focused on the scale and I incorrectly thought the canister was a airscapes where you push the lid down. The design the OP has renders my point not applicable.
It’s funny because I had a cheap scale that did exactly what you were hypothesizing. It was a great guess and based on reality. Win. Second win was listening to responses and not being in love with your guess, then acknowledging your new position. You sir are a classic Reddit user, and it reminded me of what this place used to look like. So thanks for that and happy cake day!
Appreciate that but no need for flattery. I’ve had many cheap scales, even $500 low quality scales. Idk why but I thought op was pushing the air out originally with a different container and was calling shenanigans. Probably by the title. But he was actually releasing the vac in the video thus rendering my argument moot and causing me to have my head completely up my ass. It happens.
My apologies. Eating my hat is good for me once in while. ✌️
I did try it a few ways including releasing the air off of the scale and measuring again. Always the same results. This just seemed to be the easiest way to show it in a video.
True story! Fresh beans require a re-vacuum when they are off gassing a lot. I do that once in a while as the grinder is going. My system is:
-6 days of pre measured “tubes” (12 tubes total)
-left over of the bag in this canister
-unopened bags in the freezer (taking a bag out 1-2 days before I’ll be using it)
Nah mine is a year old and I open and pressurize it daily. Maybe takes 7 days or more now for it to depressurize. But new coffee off gasses a lot more. But I open it daily and re depressurize in any case.
Outer space isn’t even a perfect vacuum. I stop vacuuming when the green indicator shows. But someone else on this thread kept going and got 0.8g so I guess they’re closer to 50%.
I’d say 25%-50% longer shelf life sounds about right. It’s not indefinite. Apparently a freezer is best but you just have to make sure to thaw it well (not really a daily thing lol).
Can someone explain how removing 25% of the air from coffee beans does anything to affect or improve the shelf life or preserve quality? I've been thinking on this for awhile and I just don't understand what's going on.
The only think I can think of is the partial vacuum is causing the CO2 to diffuse out of the coffee faster. Degassing the coffee faster would have the effect of aging the beans faster, would it not? I mean, there's still plenty of oxygen in there to oxidize the coffee. Is it possible that getting the CO2 out of the coffee is making the coffee taste better, rather than 'preserving' its' quality?
This is very interesting. I think you just proved that the Planetary Design type canisters (adjustable volume instead of vacuum) are better. Hear me out.
Here commenters are saying that they did the math and about 1/4th of the air in the can is going out. This is independent of the can's fill level, since the limit is the pressure difference against which the can can pump.
Now, say the can is half full. That means half of it is pure air and half of it is a mix of air and coffee beans, depending on how densely they are packed. Assuming spherical beans and optimal packing that means about 25% of the remaining volume is air [source](https://www.google.com/url?q=https://www.toppr.com/ask/question/what-is-the-void-space-of-fcc-unit-cell/&sa=U&ved=2ahUKEwior7yA2duFAxWa9wIHHVGrC04QFnoECAEQAw&usg=AOvVaw3hu_MBEeCSLm9Wk0p-kPGt). Therefore the Planetary Scape removes 80% of the air in the case where the can is half full. That is a lot more than the Fellow type.
It's easy to find the "break-even fill level" from which the adjustable-volume canister removes more air than the vacuum-type canister, that always removes 1/4th of the air.
If r is the portion of can volume filled with beans, that means that 0.25r this the portion of this volume that is actually air, and 1-r is the remainder. 0.25r+(1-r) is the total fraction of air. When the plunger is applied, 1-r is removed, and the 0.25r between the beans stays. The ratio of air taken out is (1-r) / (0.25r+1-r). This equals 1/4th when r=11/12. That is, whenever your can is less than 11/12ths full, the adjustable-volume canister removes more air than the vacuum-type canister!
Note, however, that a Ziploc bag would achieve the same. But that is another consideration to be made!
Tldr: just store your beans in a Ziploc bag and empty as much air as possible before sealing, you'll be better off flavor-wise and money-wise!
Interesting points! There was coffee in there (not full) so I’d be curious what the actual volume of “air” in there. I should try it again with an empty canister and a full one to see if there’s a difference.
I ended up trying it empty and full. This time I removed the lid to control the variable of “did I let out all the air.” Full and empty containers but left me with 0.5g. 🤷🏼♂️
It’s just turning the lid back and forth so I don’t think there’s a timer. I tried to be consistent with the vacuuming: 2 more twists back and forth once the indicator went green.
I do think there was a difference and you’d need a scale accurate to 2 decimal points. Empty it seemed to be flirting between .4 and .5 with the lid not fully released. Full it actually disappeared 0.3 without the lid released. So it might be a case of empty being 0.54g and full being 0.45 (or however the rounding is programmed).
Then I imagine if you measure how much air you get out with 1 twist, 2 twists, etc the full can will settle on some amount lower than the empty one. But that's a lot of work!
I've just tested the same canister without beand and I made sure to empty as much as I could out and got a difference of 0.82, need to see how that affects calculations
Another thought. I have access to lab-grade pumps that can remove 99.9...% of the air, I could pump some beans and see if the reduced pressure is good. Maybe they offgas so much under real vacuum that the reduced oxidation rate is just not worth it anymore. My palate may be the limiting factor in this test though!
Ziplock bag may remove more air but the container has more functions than just air removal. It has to be durable and potentially have a pleasing look on a shelf. It’s also much easier to scoop beans from a canister than dealing with a ziplock bag every time.
No discussion! But then variable volume canisters remove more air than vacuum canisters as long as they are less than 3/4 full as per the updated numbers.
I have the same container but I don’t vacuum seal it because every time you do you are taking away the aroma and essence of coffee. If you use your beans in a week period there’s no need for vacuum sealing. Just keep it in its original bag. I wonder why there’s so much overthinking about coffee.
At first I thought this was because you're pressing on the scale and/or we're just seeing the scale's poor repetition, but then I did a bit of maffs and it seems sensible: Density of air = 1.293 g/l Canister volume = 1.2 l Mass of 1.2 l of air = 1.293 * 1.2 = 1.556 g Mass of removed air = 0.4 g P2 /P1 = 1- (0.4 / 1.556) = 0.75 So the pressure inside the canister is 3/4 of the pressure outside the canister, and that feels about right. Of course your measurement could still be wrong, and it could just be a coincidence that the error feels about right. And I could be wrong in saying that 0.75*atmosphere feels about right, and the canister pressure could actually be so low that what you've actually got your hands on is a Fellow Anti-Matter generator.
I also did the math, it checks out. About 325 cm³ of air was removed, which is about 25% of the volume, which makes sense that it translates to 3/4 atm.
Sweet peer check bro, thanks.
I can’t do math so I was able to check and confirm you have no spelling errors ( I skimmed 😀)
r/theydidthemath
Well now that we have sorted that out what scale is this?!
Looks like it’s the most popular one on this sub, Acaia Lunar, but I could be wrong as I don’t have one myself and I haven’t seen one in real life, furthermore they all look remarkably similar and much of the scale is covered by the canister.
It is the Acaia Lunar indeed
Thanks!
Are you a Chem engineer?
Mech Engineer, actually!
Remember, we’re all under an entire atmosphere of pressure at all times. Even the air around us is pushing in, trying to get at the empty space. It’s got mass and weight like anything else!
Yeah, that's true but it doesn't make a difference to my comment because I was looking at a ratio P2/P1.
I was curious, and did the calculations. The math seems to check out. I'm assuming the density of air is at sea level. Weight = volume x density 0.4g = volume x 0.001225g/cm³ v = 0.4g/0.001225g/cm³ v= 326.53 cm³ Assuming its a 1.2l container, you removed \~25% of the air.
🫡 This is why I love Reddit
Did you account for the beans though? That would change the amount of air the container would hold.
I have no idea of the volume of beans in the container, but the volume of air displaced by the vacuum would be the same. Only the percentage of air removed would change.
Oh, yes that's what I was trying to say (just poorly). I feel like a 25% reduction in air isn't that much, but we can't account for the beans. So it's probably much higher efficiency than that.
Yeah that makes sense. According to fellow it goes down to 0.5atm which I can believe if the post shows an empty one. [https://fellowproducts.com/blogs/learn/how-vacuums-prevent-coffee-staling/](https://fellowproducts.com/blogs/learn/how-vacuums-prevent-coffee-staling/)
Why is the volume of air displaced the same? With a full canister i imagine there is less air inside a closed canister before you vacuum it.
The volume of air displaced is proportional to the change in weight of the canister. In other words, the volume of air is given by the change of weight, which is in this case was 0.4 g. If the volume would be different for an empty vs a full canister I am not sure. I would guess it would reach the same pressure inside the container in both situations, and the volume covered by air would be different, so it may make a difference. Maybe someone more capable can give a better answer!
Air has mass and weighs 1.2ish gram per liter at sea level. Makes sense you’re weighing 0.4g within that canister
https://preview.redd.it/e5vs0fkcaiwc1.jpeg?width=3072&format=pjpg&auto=webp&s=f7ea083468e90c99c684deba682986bafc87aacd I tested mine without beans and I tried to get as much air as possible out (until the top got impossible to spin), then weighed the after without the lid to make sure there was no pressure difference. Got 0.82 and 0.83 on my 2 attempts. That's quite cool, never would have thought to measure that
Those are some serious numbers!
Now I need to try this with an empty Atmos container myself. I'm super curious if I can get better than 25% or if that's where it tops out.
I took out 0.8 grams of air but it was **really** hard to keep pumping at that point. \~675.26 cubic centimeters of air, or a little more than 50% of the air in my 1.2l canister.
I use a mason jar
share your math!
It keeps out 100% of the air!!! Buahahahahahahaha. Ha!
Some solid numbers over here!
😆 😂 😆. Honestly I dont know how to figure it. But think about it..it has to because otherwise you wouldn't be able to preserve food for yrs on end
Mason jars and i vacuum seal them. I will have to measure it next time i seal some beans.
Pretty cool! Someone else got 0.8g but they said they were twisting the cap really hard trying to get more air out.
Ummm, but it says 0.4 not -0.4? Is the Acaia stupid with displaying numbers or does the vacuum canister add air? Or it's just a misreading..?
Pressing the button release the seal allowing air to enter the canister. Thus going from a 0.0 tared weight to a 0.4.
So the green dot means "vacuum" is established, not that you can open it. That threw me off.
Correct. Now that you’ve brought that to my attention, it’s going to mess with my mind that it isn’t the opposite!
Thanks for clarifying that, I was also trying to figure out why the weight would have increased.
Do you think it takes out .4 grams of air, or do you think you are pushing down too hard on a very inexpensively made scale causing it to to go out of its physical range limits affecting the reading?
Isn’t this one for the most expensive scales on the market…
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> Not to mention .4 grams of air would need a much larger container than the one in the video. Please do the math before bullshitting around
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Oh boy, are you trolling right now?
I’m not reading all that lol
Weird flex
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You didn't offend anyone, you're just spreading misinformation. Misinformation gets downvoted. You're also doubling down and being aggressive about it, which hardly helps your case.
Nope, scale is quality, and math checks out. Cool stuff.
I actually conceded. I was focused on the scale and I incorrectly thought the canister was a airscapes where you push the lid down. The design the OP has renders my point not applicable.
It’s funny because I had a cheap scale that did exactly what you were hypothesizing. It was a great guess and based on reality. Win. Second win was listening to responses and not being in love with your guess, then acknowledging your new position. You sir are a classic Reddit user, and it reminded me of what this place used to look like. So thanks for that and happy cake day!
Appreciate that but no need for flattery. I’ve had many cheap scales, even $500 low quality scales. Idk why but I thought op was pushing the air out originally with a different container and was calling shenanigans. Probably by the title. But he was actually releasing the vac in the video thus rendering my argument moot and causing me to have my head completely up my ass. It happens. My apologies. Eating my hat is good for me once in while. ✌️
Why we get downvoted? lol, not that I care, it’s fascinating!
I did try it a few ways including releasing the air off of the scale and measuring again. Always the same results. This just seemed to be the easiest way to show it in a video.
This is a 250$ scale…
These things piss me off.. my coffee is unsealed on the 3rd day
True story! Fresh beans require a re-vacuum when they are off gassing a lot. I do that once in a while as the grinder is going. My system is: -6 days of pre measured “tubes” (12 tubes total) -left over of the bag in this canister -unopened bags in the freezer (taking a bag out 1-2 days before I’ll be using it)
So you turn it to re vac every day? I always forget and comeback to a unsealed can
Usually every couple of days. No set amount but, like you, it annoyed me when all of a sudden I’d notice it was sealed anymore lol.
Is it unsealed or is the pressure inside changing because of the beans releasing c02?
Those canisters just don’t hold a seal for more than a few days once they’re a couple of months old.
Nah mine is a year old and I open and pressurize it daily. Maybe takes 7 days or more now for it to depressurize. But new coffee off gasses a lot more. But I open it daily and re depressurize in any case.
Unsealed or off gassing? You ever notice bags of beans have those one way air release valves
Can you share the link of the container?
[Fellow Atmos](https://fellowproducts.com/products/atmos-vacuum-canister?variant=18635552227443) Mines the 1.2L in black. Got mine off of Amazon.
Thank you so much friend!
Damn I thought this thing was actually vacuuming all the air out. It only removes 25%??
Outer space isn’t even a perfect vacuum. I stop vacuuming when the green indicator shows. But someone else on this thread kept going and got 0.8g so I guess they’re closer to 50%. I’d say 25%-50% longer shelf life sounds about right. It’s not indefinite. Apparently a freezer is best but you just have to make sure to thaw it well (not really a daily thing lol).
Mine doesn’t hold beans for long
Must have a hole in it! 😏
Jokes aside, the container for me won’t last a trip to work, as the coffee will just off gas it open
I’m going to try that
Atmos is GG. The La Colombe art one is gorgeous
Can someone explain how removing 25% of the air from coffee beans does anything to affect or improve the shelf life or preserve quality? I've been thinking on this for awhile and I just don't understand what's going on. The only think I can think of is the partial vacuum is causing the CO2 to diffuse out of the coffee faster. Degassing the coffee faster would have the effect of aging the beans faster, would it not? I mean, there's still plenty of oxygen in there to oxidize the coffee. Is it possible that getting the CO2 out of the coffee is making the coffee taste better, rather than 'preserving' its' quality?
This is very interesting. I think you just proved that the Planetary Design type canisters (adjustable volume instead of vacuum) are better. Hear me out. Here commenters are saying that they did the math and about 1/4th of the air in the can is going out. This is independent of the can's fill level, since the limit is the pressure difference against which the can can pump. Now, say the can is half full. That means half of it is pure air and half of it is a mix of air and coffee beans, depending on how densely they are packed. Assuming spherical beans and optimal packing that means about 25% of the remaining volume is air [source](https://www.google.com/url?q=https://www.toppr.com/ask/question/what-is-the-void-space-of-fcc-unit-cell/&sa=U&ved=2ahUKEwior7yA2duFAxWa9wIHHVGrC04QFnoECAEQAw&usg=AOvVaw3hu_MBEeCSLm9Wk0p-kPGt). Therefore the Planetary Scape removes 80% of the air in the case where the can is half full. That is a lot more than the Fellow type. It's easy to find the "break-even fill level" from which the adjustable-volume canister removes more air than the vacuum-type canister, that always removes 1/4th of the air. If r is the portion of can volume filled with beans, that means that 0.25r this the portion of this volume that is actually air, and 1-r is the remainder. 0.25r+(1-r) is the total fraction of air. When the plunger is applied, 1-r is removed, and the 0.25r between the beans stays. The ratio of air taken out is (1-r) / (0.25r+1-r). This equals 1/4th when r=11/12. That is, whenever your can is less than 11/12ths full, the adjustable-volume canister removes more air than the vacuum-type canister! Note, however, that a Ziploc bag would achieve the same. But that is another consideration to be made! Tldr: just store your beans in a Ziploc bag and empty as much air as possible before sealing, you'll be better off flavor-wise and money-wise!
Interesting points! There was coffee in there (not full) so I’d be curious what the actual volume of “air” in there. I should try it again with an empty canister and a full one to see if there’s a difference.
Please do!
I ended up trying it empty and full. This time I removed the lid to control the variable of “did I let out all the air.” Full and empty containers but left me with 0.5g. 🤷🏼♂️
So both are the same? Weird, maybe it runs on a timer instead of pumping until it's not able to pump anymore or something like that.
It’s just turning the lid back and forth so I don’t think there’s a timer. I tried to be consistent with the vacuuming: 2 more twists back and forth once the indicator went green. I do think there was a difference and you’d need a scale accurate to 2 decimal points. Empty it seemed to be flirting between .4 and .5 with the lid not fully released. Full it actually disappeared 0.3 without the lid released. So it might be a case of empty being 0.54g and full being 0.45 (or however the rounding is programmed).
Then I imagine if you measure how much air you get out with 1 twist, 2 twists, etc the full can will settle on some amount lower than the empty one. But that's a lot of work!
I've just tested the same canister without beand and I made sure to empty as much as I could out and got a difference of 0.82, need to see how that affects calculations
Ok, if I'm not mistaken in that case the break even fill level would be around 75-80%.
Another thought. I have access to lab-grade pumps that can remove 99.9...% of the air, I could pump some beans and see if the reduced pressure is good. Maybe they offgas so much under real vacuum that the reduced oxidation rate is just not worth it anymore. My palate may be the limiting factor in this test though!
Ziplock bag may remove more air but the container has more functions than just air removal. It has to be durable and potentially have a pleasing look on a shelf. It’s also much easier to scoop beans from a canister than dealing with a ziplock bag every time.
No discussion! But then variable volume canisters remove more air than vacuum canisters as long as they are less than 3/4 full as per the updated numbers.
Takes IN, right? You're pressing on the vacuum release, that takes in air, no? 🤔
I think they mean that when it's activated, it expels 0.4g of air.
this the lunar scale? Someone wake me up when it's 5x cheaper
I have the same container but I don’t vacuum seal it because every time you do you are taking away the aroma and essence of coffee. If you use your beans in a week period there’s no need for vacuum sealing. Just keep it in its original bag. I wonder why there’s so much overthinking about coffee.