Should coffee be vacuum sealed? - Page 2

Want to talk espresso but not sure which forum? If so, this is the right one.
Nate42

#11: Post by Nate42 »

jpender wrote:
One big problem was that he just stuck the beans in those contraptions and left them there for six weeks. That's not how most people would use a storage container like this. Most people would open them, probably every day. The repeated introduction of oxygen would likely have an effect that James's test wouldn't be able to measure. And as a simple control he could have compared it to just using the bag the coffee came in or maybe a ziplock.
Pretty sure he said he opened them daily to simulate use. I agree with you that there should have been a control, but his justification is that he considered the simpler containers to be basically equivalent to leaving it in the bag.

jpender

#12: Post by jpender »

Where in the video did he say these things?

ojaw

#13: Post by ojaw » replying to jpender »

Mentioned it just below the vid.

Nate42

#14: Post by Nate42 » replying to ojaw »

yeah, sorry hadn't watched it since it first came out so lost track of what was in the video and what was in the comments. There is some additional discussion of process in both the video's description and also in the comment section.

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Randy G.

#15: Post by Randy G. »

FWIW..

There have been various claims made over coffee freshness preservation over the decades. The one-way valve in retail packaging was one of the earliest and their only real value is to keep the bags from bursting from the buildup of CO2. This is factual- I shipped four, 1/2 pound bags of fresh home roasted, vacuum sealed, to my brother in a flat rate box. I had forgotten to put a pinhole in each bag, and be said when it arrived (about two days later) the box was nearly a sphere. Another was the Friis Coffee Vault which I reviewed about 8 years ago which makes for an entertaining read as their claims were quite far fetched and never supported with any factual information. They even claimed that the CO2 was harmful to the taste of coffee.

In terms of taste:
- Bad For Roasted Coffee Beans: heat, oxygen, sunlight, time
- Good For Coffee: Avoid the above as best you can, then grind, brew, drink.. in that order

I avoid vacuum packing roasted coffee. If you pull a partial vacuum in a jar then later open the jar, on a basic level, what you are doing is vacuum-marinating the beans in oxygen each time the jar is opened.
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tiptongrange

#16: Post by tiptongrange »

I use these small jars that have one way valves, and bought two 4 container sets so that I have eight containers. I roast once a week and put a one day supply of roasted beans in each container so that the beans are exposed to oxygen only on the day they are used.

These particular containers don't seem to be available now but you could do the same thing using small mason jars with one way valve lids. Here's a link to small mason jars:
4oz Mason Jars

And here are links to a few one way valves for them:
4-Pack of Fermentation Lids with Extractor Pump for Wide Mouth Mason Jar

Home Fermenting Lids Kit Waterless Airlock For Wide Mouth Mason Jar

Fermentation Kit for Wide Mouth Jars - 4 Airlocks

RyanJE

#17: Post by RyanJE »

Randy G. wrote: I avoid vacuum packing roasted coffee. If you pull a partial vacuum in a jar then later open the jar, on a basic level, what you are doing is vacuum-marinating the beans in oxygen each time the jar is opened.
Randy,

What does this mean, can you explain? Vacuum marinating beans in oxygen?.. I vac seal then freeze in mason jars so I'm interested.
I drink two shots before I drink two shots, then I drink two more....

aussiecoffeebuzz

#18: Post by aussiecoffeebuzz »

I can't see why vacuum sealing isn't preferable.
isn't it oxygen that causes the coffee to deteriorate over time?

vacuum sealing reduces the amount of oxygen available to make contact with the beans.

if you use a vacuum sealed bag rather than a tin, it collapses because of the atmospheric pressure pushing on the outside of the bag - so the pressure on the beans doesn't change.

if CO2 is given off by the beans ... the vacuum seal should relax over time - I haven't seen this, even after 1 month of storage in a vacuum sealed bag the vacuum sealed bag is tightly collapsed around the beans.

would love to hear an argument for not vacuum sealing from someone with a physics / chemistry background ... given how nerdy (myself included) coffee enthusiasm is - there must be someone on here who fits the bill.

jpender

#19: Post by jpender »

aussiecoffeebuzz wrote:if you use a vacuum sealed bag rather than a tin, it collapses because of the atmospheric pressure pushing on the outside of the bag - so the pressure on the beans doesn't change.
That's only true where the beans contact the bag. Where the beans are in contact with one another I think the pressure will be higher. And there is still a substantial amount of bean surface area that doesn't touch anything and will be at the vacuum pressure.

aussiecoffeebuzz wrote:if CO2 is given off by the beans ... the vacuum seal should relax over time - I haven't seen this, even after 1 month of storage in a vacuum sealed bag the vacuum sealed bag is tightly collapsed around the beans.
How much CO2 will need to evolve per gram of coffee in order for the package to loosen? Assume a 25% void and a packing density of 0.35g/cm3.

aussiecoffeebuzz wrote:would love to hear an argument for not vacuum sealing from someone with a physics / chemistry background ... given how nerdy (myself included) coffee enthusiasm is - there must be someone on here who fits the bill.
The idea, which a search of this site will uncover numerous instances of people discussing, is that the boiling point of a substance is a function of total pressure. So, the theory goes, volatile aromatics will boil off coffee beans in a vacuum. I think this notion is incorrect but it is an argument that has been made against vacuum sealing.