Fridge, freezer or shelf: What to do when storing beans for longer periods of time

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[edit] Fridge, freezer or shelf: What to do when storing beans for longer periods of time

So you're going on a holiday or the boss has sent you on a surprise business trip and you just roasted a giant batch of your best coffee to date? Maybe you forgot that the missus had planned a longer stay with the in-laws and you accidentaly ordered a lot of coffee you can't get yourself to throw away. Whatever reason you have for wanting to store your beans for a longer time, the question remains: What is the best storage option?

Ok. We all know that you shouldn't store your beans for a longer period. Always buy small amounts and order more often so that the coffee always is fresh. But every now and again we get this question at the shop and we wanted to find out personally what the right answer should be. I originally posted this experiment on my blog but decided to give it a rewrite and share it with my fellow coffee lovers here at TMC.

The taste panel in the experiment consisted of Tim Varney, Tim Wendelboe, Chris Kolbu, Ingrid Fossheim Karlsen and myself Ola Brattås. Here's how it all went down:

Disclaimer: Please keep in mind that there are several aspects of the storing of beans we have left out completely to make the experiment more managable (repeatedly opening and closing of bags, different storage containers etc), and that these aspects might have an impact when you store your beans. We have only used one way valve bags and left them unopened in the different places of storage before cupping them.

Part 1: I filled 9 oneway valve bags and filled each with 100g with coffee before sealing them. The coffee I used was a La Esperanza CoE, Colombia roasted on the 8th of August. I placed three of the bags in the freezer, three in the fridge and three on the shelf out of the sunlight in our cupping room.

I’ll be opening the door of the freezer and the fridge each day at least to mimic normal behavior in the kitchen of our customers. I know there are several weak points to this test, but it is not meant to be 100% scientific. It’s more of a fun project that hopefully will give some answer and perhaps some surprises.

Over the next four weeks we’re going to cup them to test how the different storage methods has affected them. I’ll post our cupping notes after each cupping. We’ll open the first three bags (one from each storage version) on the 29th of August (two weeks into the experiment), then another three on the 5th of September (three weeks in) and the last three on the 12th of September (after four weeks).

The purpose is to see what is the best to recommend our customers when they ask how to store their coffee. Our normal answer is to buy small quantities and drink it within roughly two weeks after the roast date, but there are always people who insist to do it differently for one reason or the other. I’d like to try to find out for myself what is the optimal way for storing your beans over longer periods of time.

Part 2: Today it’s been 2 weeks since we put the bags of coffee in the freezer, fridge and on the shelf as I’ve described in my previous post. It was time to taste the first three bags. Originally we described the flavour of the coffee as being fresh and fruity with a light citrusy acidity. The taste is of light red berries and it has a clean and sweet finish.

When I took the bags of coffee out I noticed straight away that there seemed to be more air in the bag stored in the fridge, whilst the bag stored in the fridge was moist on the outside. We left the bags of coffee on the counter to thaw and to reach room temperature.
 I organized everything as a normal cupping; weighing up the beans to a ratio of 55 grams per liter. To our cupping cups this means 12 grams of coffee.

We examined the leftover beans for possible visual differences and it turned out that the beans left on the shelf had gotten an oily sheen, the beans from the fridge where quite matt with the beans stored in the fridge being somewhere inbetween. The coffee was roasted for french press and other normal brewing devices and were lighter than for espresso. They were dumped before second crack so they did not have an oily sheen to begin with.

We lined up six different cups with the three different beans (two of each) and randomized them. I had marked the cups underneath so we could see which was which after the cupping.

Tim (Varney) and I started the cupping and smelled the grinds before adding water. There where some differences in the strength of smell. The one from the freezer had the most intense smell when it was dry with the ones from the shelf coming in second.

After adding water the beans having being stored in the fridge had the strongest aroma with the ones from the shelf still coming second.

Tim (Wendelboe) and Ingrid joined in after we had broken the crust and had let the cup cool enough to taste. We weren’t completely in sync, but we finally reached the conclusion that the coffee having been stored on the shelf retained more sweetness and had a better acidity. The beans from the freezer had become more flat and boring, not showing any of the pleasant acidity that had been in the original cup. The beans having been stored in the fridge had become bitter and unpleasant and were rated dead last.

The final score after two weeks of storage is:
1. Shelf
2. Freezer
3. Fridge

I can’t wait until next week when we take out the next three bags and see what has happend after another seven days of storage has passed. Has the fridge-beans kept better than the others or does the conclusions remain the same? Will Chris have anything to add to the taste panel when he returns from his vacation in Bulgaria?

Part 3: Today was week 3 of the storage experiment. The coffees had today been stored for 3 weeks in the freezer, fridge and on the shelf. It was time for the second cupping.

I took the bags out early to make sure they were properly thawed before the tasting started. The proceedings went on as last time, and todays cuppers were Tim Varney (espressobar manager at Tim Wendelboes), Tim Wendelboe himself (coming in to the cupping at a late point but adding valuable input), Chris Kolbu (part-time barista and recently returned from vacation. He came in to the cupping a bit later on), an unsuspecting customer wanting to participate in our daily cuppings and finally myself.

Today I included a control sample in our line-up; a La Esperanza roasted a week ago to the same roast degree. It proved to make an interesting point.

In this cupping we gave the coffees 6 points for first place, 4 for second, 2 for third and 0 points for fourth place. The jury seemed a bit divided, and even though the points added up to give us a order to rank the coffees in the end there wasn’t a clear consensus. Two of the cuppers actually preffered the coffee having been stored on the shelf for three weeks to the fresh control sample. Their names remain secret to protect them from shame and utter humiliation…

So without further ado I present this weeks ranking of the stored coffee (the difference from last week being of course that we included the control sample, and if you exclude it you get the results to compare with last weeks cupping):

1st place: The control sample with 26 points
2nd place: The shelf stored coffee with 14 points
3rd place: The fridge stored coffee with 10 points
4th place: The freezer stored coffee with 8 points

The conclusion is that the coffees seemed closer this time around than they did last time. The shelf stored coffee still seem to have an edge, but the two other samples are scored mostly equally. The descriptions given by the cuppers also seemed to put all three storage methods closer together and it seems like that at this point three weeks into the experiment there isn’t that much of a positive difference between the storage options. It’s also clear in my mind (even though the two unnamed cuppers inadvertently gave 6 points to the shelf stored coffee instead of the control sample) that to store coffee for this long should be avoided if possible.

Part 4: So today it’s been 4 weeks since we started the experiment and it was time for the last cupping. We’ve changed our cupping schedule from 14.00-15.00 (2 pm to 3 pm) to 16.00-17.00 (4pm to 5pm). This meant that we weren’t in the middle of the late lunch-rush when the cupping began. This in turn made it easier to focus while cupping.

As before we ground up 12 grams of the three differently stored coffees and a control sample. We later decided to skip the control sample as that coffee had been roasted slighlty darker and wouldn’t serve it’s purpose.
 Tim Varney volunteered to start the cupping and to get his “ugly mug” on the blog again to illustrate our cupping procedure. The other cuppers were Tim Wendelboe and myself.
 As dry grinds there were no distinction between the 3 cups. We then boiled the water…
 …and poured it onto the coffee. There were a slight distiction between the cups when the water had been added but not so much that we could agree upon one cup being more aromatic than the other.
 After having broken the crust and removed the foam we tasted the three coffees and this is were the differences became apparent. First of all; like last time we agreed on that no coffee should be stored this long no matter what method of storage being used. The coffees flavours had faded even more during the last week. But this is where we stopped agreeing. We scored and valued the 3 cups differently, but settled the score with …eh summing up the scores.

This time we gave the cup we preferred 6 points, the cup in second place 4 points and the least preferred cup 2 points. By summing up the points given by the three of us we could declare a winner…
 1st place: The freezer with 12 points
2nd place: The shelf with 10 points
3rd place: The fridge with 8 points

There wasn’t that much between the contestants this time around either, but the coffee from the freezer seemed to have an edge. I guess that this coffee would have increased it’s lead if we were to go on for more weeks. But why would anyone want to store their roasted coffee for that long?

As a conclusion for the entire project it seems that it’s better to store your coffee on the shelf out of sunlight and in an airtight container for up to 3 weeks rather than storing it in the same container (unopened) in the freezer and the fridge. But if you are going to store it for 4 weeks or longer (for some strange reason) you should store it in the freezer. This is true for coffee roasted for drip or french press. In case you have coffee roasted for espresso the freezer has an even bigger positive effect according to Tim W (having done a similar with this kind of coffee).

My theory is that the freezing and thawing process affects the coffee negatively but being frozen the coffee deteriorates more slowly than when stored on a shelf. For shorter periods of time the process of freezing and thawing makes the coffee from the freezer taste worse, but over time the deterioration of the coffee stored at room temperature is greater and will pass the combined effect of freezing/thawing added to the gradual deterioration of the coffee from the freezer.

We still have many questions unanswered. What would have been the differences between the coffees after 1 week? What would happen to a coffee that was less acidic? What if we opened and closed the bags every day?

This material for another experiment, but we'll leave it for another time.

Hopefully this test has had some value for you and might have answered some questions that you might have had. If you have any suggestions for things you'd like us to test out feel free to contact me via PM or my blog.