Ran a series of side by side taste tests with:
A) two 100g vacuum sealed bags of beans that were vacuum sealed the prior day, after 2 weeks rest in their original bag. The first 100g bag of beans was then decanted into 6 mini jars that hold 18g, which have a cork plug. The jars were filled to the brim and then closed with the cork plug.
B) two 100g vacuum sealed bags of beans that were vacuum sealed after 2 weeks rest in their original bag. These were subsequently frozen, for 1 day. One bag was then removed from the freezer the evening before the test and defrosted overnight. The next morning, the defrosted beans were decanted into the above mentioned glass jars.
I tasted a pair of never frozen vs frozen then defrosted bean jars (18g per) every day. Each pair was ground and poured in the same manner. However I did vary the brew ratio from day to day, as I was testing the affects of various brew ratios on taste. But the paired shots were always ground and poured in the same way.
Once I worked through one set of 100g bags, I would work through the next set.
I noticed that the never frozen shots initially tasted just slightly (oh so slightly) better than the frozen then defrosted shots. By better I mean more body, strength, taste extraction and length. But just slightly.
However this barely detectable effect (of the never frozen beans tasting just barely better than the defrosted beans) only lasted a day or at most two. By the end of the week, there was a discernible difference between the never frozen vs defrosted beans. This divergence continued and widened with the next paired 100g bags of beans, with the never frozen beans declining further, as if they were staling.
This divergence should not have occurred, as the never frozen beans were apparently decently vacuum packed using an inexpensive home vacuum sealing machine.
I conjure that once the never frozen beans beans left their original bags (which were sealed one pound bags with one-way valves), they were exposed to oxygen and began an irreversible decline. Moreover the vacuum packing process did not likely remove all of the oxygen. So the beans continued to stale in the vacuum sealed bags. This staling likely accelerated upon the opening of the vacuum sealed bags, and their decanting to the jars.
At the end of the 12 day series, I was effectively tasting 12 day old (stale) beans vs 6 day old defrosted beans. I had to throw out the never frozen beans, as they were too stale.
Conclusions:
While freezing beans might cause a very slight loss in the potential to extract good shot body, strength and taste, this is over shadowed by the preservative benefits of freezing beans.
By comparison, once you open a bag of never frozen beans, they will begin to stale, even if you reseal them in vacuum bags (with my home vacuum sealer). Once you open the vacuum sealed bag, the staling process will accelerate, even if you decant the beans to well sealed glass jars.
The only time that never frozen beans taste better than defrosted beans, is when the original bag of beans is opened, after 2 weeks rest. After that, taste goes gradually downhill.
So, I will be freezing my beans in 100g vacuum sealed packets, after 2 weeks rest. And then decanting a single defrosted 108g packet into six 18g jars, but with silicone rubber stoppers.
All of the above is subjective and not perfectly scientific, but its good enough for me.
PS. The beans were a blend of decaf Hawaiian and decaf Espresso blend (â
Hawaiian and â
Espresso blend), roasted by Goldstar coffee.