I personally have found that if you can pack coffee correctly within 1
hour or so of roasting, it can give GREAT results. This is born out my my Naked
portafilter video on the coffeetime website with
a 9 day old bean .
If you pack into a standard jar, as the
pressure builds, the gasses remain in the jar under pressure and the Oxgen also
remains. Under pressure , oxygen will be
even more reactive and the staling process will actually be enhanced. The idea
of the one way valve at the top of the
jar is to allow the oxygen to be flushed out.
Theory:
Beans give
out Carbon Dioxide (CO2). CO2 is heavier than Oxygen so sits at bottom of jar
and effectively all the oxygen in forced out, because the valve is at the top,
(unlike a coffee bag). CO2 acts as a natural preservative for coffee. All this of course only does any good until the moment
you open the lid.
For this whole thing to work succesfully, the
jar has to be as full as possible and sealed up whilst the beans are degassing
and before oxygen has a chance to start working on them. So it's for the
longer term storage of beans, but normal staling will begin the moment you break
the seal, obviously the staling/rancidity will still happen in the jar, but it
is slowed down.
I have had beans in a Valve bag (overfilled slightly)
sealed correctly and degassed at an angle. I have opened them after 3 weeks and
they are pretty good...BUT packed within an hour or so after roasting.
At no time keep the beans in the fridge or freezer, in my experience
this ruins the taste.
So on to the project:
My first ideas
I tried using storage jars with clip down lids. The acrylic tops were
hard to drill and prone to cracks as you can see. Other similar jars have steel
tops and these would be hard to drill. Tape was used to seal the valve in and
seal the cracks.
The downside of this method is the difficulty to make and the cost of the
jars.
The final product
I have always been interested in recycling and thinking about an
environmentally friendly method, led me to the final, and I feel most suitable
method. The use of old food jars, these can be small jam jars, or quite large
pickle/mayo jars with metal lids (the lids are thin and easy to
drill/grind). It's not only free, but good for the environment as these
things are normally just thrown away.
My first "recycled" 1 way valve jars. I had 3 old jam jars and successfully
made them into 1 way valve jars. I am quite pleased, because this is one of the
big areas of recycling "reuse" and anyone who knows me, also knows, I try to
take the environment seriously (I even have an eco-car ).
I suppose jam jars are in a sense an ideal size as it allows long term
storage of smaller portions of a roast, each portion only being exposed to
oxygen by opening ("breaking the seal") when you need to start using it.
For those who want to try making some, the "manufacturing" process is quite
easy.
Tools required
Hot melt glue gun
(small) 6-8mm metal drill bit Small drill mounted grinding stones (use a
conical one), Focus DIY sell 5 stones in a blister pack for £1 Jam Jars with
metal lids Some old coffee bag one way valves (cut from pack, just cut
around the valve body)
Procedure
Drill lids of jars
(use block of wood to support lid) Enlarge and deburr hole by using conical
grinding stone in drill (both sides), enlarge hole to about 10mm Run v small
bead of hot melt glue around hole (not too much) Press valve onto glue
(always the foil side of valve on to glue). Depending on valve this may mean
valve body is inside or ouside of jar (innie or outie). Be mindful of the way
the air needs to flow! Run bead of glue around rim of valve (to seal it to
lid)
That's it, you are done. It takes around 10 minutes to do 3 jars.
If you ever need to change the valve, the hot melt glue actually comes off
really easily.
Why do I like these best of all:
Recycled Airtight Washable (except lid) Easy and
quick to do Valve can easily be replaced if necessary Cheap/Free Allows CO2 gas to push oxygen out, preserving coffee for longer
(Oxygen can get trapped in top of valve bag).
I was thinking about
searching for a different type of valve a more high quality brass, spring and o
ring type affair. Not sure what yet, but have my thinking cap on.....for now
though, old one way valve bags valves will have to do.
).
