I wanted to test my theory that vacuum sealing individual 18 gram doses of roasted coffee beans (versus storing them in a standard one-way valve coffee bag) would extend the number of days of what I call “peak freshness”. The latter phrase describes the number of days where I enjoy the fullest flavor of the espresso.
To test my theory I kept some beans from the same roast in a normal coffee bean storage bag with a one way valve and others in individual 18 gram dose vacuum sealed bags.
The beans were Kenyan “Lena AA” and were roasted on Monday 9th May 2022. The vacuum sealing was done on Tuesday 17th May which was when I guessed they were at the start of peak freshness. The beans were a dark roast and measured 64 on the Agtron scale as measured by a Tonino colour analyser.
My test pours were conducted on Thursday 14th of July 2022 so around 58 days or close to 8 weeks after vacuum sealing.
I made six espressos, three from the standard bag and three from the vacuum sealed bags. I used 18 gram doses for each one as measured on a calibrated Acaia Lunar. I used a Weber EG-1 set to the same dial point for each grind and I used a Decent DE1XL with the “Adaptive” profile for the pour. I used these two machines (EG-1 and DE1XL) because they offer the most consistency from the machines available to me. The espressos were all ground and poured one after the other so that there would be no significant change in room temperature or humidity from one grind/pour to the next.
In short, I tried to make every variable consistent, as far as reasonably possible, with the exception of the beans coming from either the standard bag or the vacuum sealed bags.
The results consistently showed that the vacuum sealed beans had disintegrated* faster than the beans stored in the standard one-way valve coffee bean bag.
(*I am not sure if “disintegrated” is the right word, maybe it should be “dried out” so feel free to suggest a more apt word/phase).
The two pics are typical of the pours. One pour each from the vacuum sealed pouches and the beans from the traditional bag. They pics are of the DE1XL screen and show that it took 15 seconds for the vacuum sealed beans to hit the 36 gram mark and 18 seconds for the beans from the standard one-way valve bag to hit the same mark.
My previous theory was that the lower amount of oxygen in the vacuum sealed bags would decelerate the disintegration of the beans. But the opposite has happened which leads me to think that perhaps the gas given off by the beans in the sealed environment is accelerating the disintegration in much the same way that a bunch of bananas contained inside a sealed plastic bag ripens faster due to the gas given off by the bananas being unable to escape.
In hindsight, this makes sense. And that’s the funny thing about hindsight: we are all so wise after the event but only a few seem to figure these things out in advance. I guess that’s why we need to test theories for ourselves rather than just take someone’s word for a thing, however logical their rationale may sound.
Anyone want to contribute their two bob’s worth?