Why Coffee Loses Flavor

in Brewing Coffee, Coffee Maintenance

It’s a travesty.  While I might be anxious to get through this coffee overstock, there was nothing good about what happened this week.  I was excited to finally break open a pound of Kenya AA coffee bought for me by a friend.  He had bought it for me over a month ago so naturally I was concerned about how fresh it would be.  A few weeks ago, I vacuum-sealed it in the hopes that it would hold some freshness.  Coffee are like cigars to me in that way, a slightly stale quality cigar can still be better than a fresh low-grade cigar.  With coffee, flavor comes from freshness.  The more fresh the coffee, the more flavor in the cup.

The travesty is that not only did I have to throw out this pound of coffee, but Kenyan coffee is one of my all-time favorites.  Kenyan coffee is sold at state-run auctions in Kenya, and the AA grade means it’s Kenya’s finest.  It was the worst coffee since I had to drink cafeteria coffee last year.  Don’t let it happen to you.  Let’s look at how you lose flavor in coffee.

Flavor = freshness.  And there are four enemies to coffee freshness: they are oxygen, moisture, heat, and light.  The point is not to allocate blame, but to decide what both the roaster and I might have done wrong that took all the flavor out of what should have been a great coffee.

The most common enemy: air.  Exposure to air is inevitable and very little is truly air-sealed.  I had this coffee a while after it was bought so I have to take responsibility for not getting to it fast enough.  Having said that, the roaster did not indicate on the bag how recently it was roasted and I was surprised how little flavor it had left, even if I sat on it for a month.  Choose a roaster that indicates how recently the beans were roasted so you know how long they’ve been expiring.  Peet’s Coffee and Tea indicates on the bag on what exact date the beans were roasted.

When beans are done roasting, the roaster has to cool them down.  Otherwise, they will continue to roast on their own from the heat in the bean’s interior.  Make sure your roaster does not use a liquid technique to cool down the beans.  This moisture will also sap freshness from the bean.  This is also a concern if you freeze your coffee, which causes moisture once the beans are removed from the freezer and thawed.

Heat and light
I lump these two together as secondary possible causes.  Oxygen exposure is likely the biggest cause by both the roaster who did not package and sell these beans quickly enough after they were roasted, as well as the time they spent on my shelf before I got to them.  Moisture exposure is another possible defect in the roaster’s process.  But heat is more of a concern during the brewing process, and certainly, you don’t want to let your coffee sit on heat for too long before it’s poured and enjoyed.  Light can also take away from coffee bean freshness, so it’s suggested you store your beans in a cupboard, which I had done so this isn’t likely what I did to cause the beans to lose freshness.

It is a very real possibility that the roaster overheated the beans, possibly not cooling them at all after they were roasted, so heat exposure could have been a cause.


  1. Do broken coffee beans lose their flavor? I always remove broken beans before brewing and my coffee tastes fresh even at the bottom of a two pound bag kept in the freezer.

    Comment by Anonymous — September 5, 2016 @ 7:45 pm

  2. Broken coffee beans shouldn’t lose their flavor. The key to good coffee roasting is inner bean development, so that even if the bean broke, its parts still retain the flavor. If the inner bean was not properly developed by roasting, then it is possible that a part of the inner bean separated from the exterior would be flat in flavor.

    Comment by Marc Wortman — September 6, 2016 @ 11:35 am

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