Testing for Coffee Shelf Life

Packaging and the maintenance of packaging equipment is one of the biggest challenges in the roasting facility. Coffee Analysts has designed shelf–life tests so that several samples from a batch are tested at once. Especially in the case of coffee packaging, only testing one bag will not give adequate information about the packaging system.

Use of the leak detector: When excessive oxygen is found, it is important to determine the source. If the equipment is not sealing the bag properly, pinhole leaks can develop that allow small amounts of oxygen into the package over time (immediately after manufacture, no oxygen will be detected). By isolating the location of these leaks, the equipment can be adjusted as necessary.

Often, no leaks are detected in a package with excessive oxygen. This can be a sign that the bags are not being fully flushed with nitrogen, possibly as the result of the packaging line moving too fast.

Valve Bags

For packages with valves, testing for both carbon dioxide and oxygen is recommended. If the coffee was packaged soon after roasting the carbon dioxide level can be as high as 80% after a week. If no carbon dioxide is found in a plastic-covered pinhole valve, the shelf life of the product may be limited.

Fractionally Packaged Coffee

For serving size roasted ground coffee, it is suggested that a random case of product be sent for analysis. All bags are quickly checked for leaks and 20% of the total are tested for oxygen and leaks.

Other Shelf Life Issues

Coffee shelf life samples compared

Coffee shelf life samples compared

Where oxygen is the main fuel for staling, excessive moisture absorption accelerates the staling process. For this reason, water activity (the ratio of free water to bound water) is also measured. Work done at the University of Minnesota by Dr. Ted Labuza show that when the water activity is raised to 0.35, the rate of staling increases dramatically. A more ideal level for a medium–roast coffee is 0.20–0.22. Excessive water activity indicates that the coffee was in contact with humid conditions for an extended period of time before packaging or that the package material is an inadequate moisture barrier.

7 comments to Testing for Coffee Shelf Life

  • I’m hoping you can help me. I am in a long-standing heated debate about using 3-4 year old individually packaged ground coffee. It also has not been stored at consistent temperatures. To me, it tastes and smells stale and rancid but I am somewhat of a purist when it comes to coffee. The owner says it’s fine, serve it. I don’t want to serve anything that I wouldn’t, myself consume. Someone went on Yahoo answers and one of the yahoos there said ground sealed coffee keeps for a few years. I don’t see how this can be true when whole beans don’t even last a year. What is your expert opinion?

  • Hi Michelene,

    You are correct. Coffee begins to go stale immediately after roasting and the process is acclerated when ground. Even being stored in a nitrogen flushed frac pack, which sounds like the one you described, a long life would be 6 months. The first indicator is the smell of the fragrance and then the aroma. It should be plentiful and light/pleasant. If it’s lacking then it’s stale. Stale coffee tastes cardboard like and rancid coffee tastes like rotting vegetables & fat. If you check out our website we list a staling chart which might be helpful.Customers buying coffee deserve to be served fresh coffee.

  • I´m Hoping you can help me with a testing for shelf life in instant coffe and roasted coffee, I need, a table with a relation of temperature and the time of shelf life, if it exist.
    By the other hand if you have any information of the equivalence in time in shelf life accelerated test VS real shelf life.

    Than you and best regards.

    Please answer to my e-mail: josmendg@gmail.com

  • avatar Thanh Tran

    Could you please to give me advices on shelf-life testing of R&G coffee.
    - Temperature and Humidity to store the sample
    - Parameter need to test
    - Accelerated method for shelf-life testing of R&G coffee.

    Thanks

  • avatar melissa

    Great post and very informative! I am in the coffee business myself, and we roast, let off gas one day, then nitrogen flush the bag and beans before sealing in foil one way valve bags. We just got going with the nitrogen flushing and are trying to find out how we can test the oxygen content of a sealed bag. Anyone out there know of the right machine or technique for this? Thanks!!

  • avatar Staff

    Hi Thanh,
    We do not know exactly how to answer your questions. If you have a specific need for coffee research, please contact us at: spencer@coffeeanalysts.com or call: +1 802.864.5760.

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