I have spent the better part of the past decade more or less obsessing over green coffee preservation. It is my belief that this is the portion of the industry which has received the least amount of attention in recent years. Those of us old enough to remember a time in specialty coffee when not every lot came with a bag liner (i.e. Grain Pro/Ecotact), will recognize that this has been the single greatest advancement in coffee preservation in the past twenty years. While it is somewhat surprising to me that development in this area has more or less stalled, it is not entirely shocking. Warehouses and shipping containers are quite a bit less appealing and Instagram-worthy than producers, farms, roasting facilities, brewing equipment, and coffee bars. As techniques in producing, roasting, and brewing coffee continue to change and advance with (sometimes alarming) regularity and alacrity, I believe that it is time for coffee roasters to consider bringing their green coffee preservation up to date with techniques that some in the industry have been using for decades.
I first froze green coffee ten years ago, in 2011. To be clear, this was by no means my idea. I had heard of George Howell having great success preserving the quality of green coffee through freezing (since 2001) and I was eager to try my hand at it on a small scale. I had been working for a company that was going through some growing pains. As is common for a roastery, these growing pains were felt most acutely through our green coffee program. For many months I was confronted with old tasting coffee day in and day out. Anyone who has dealt with this situation knows that you simply have no good options. Many would consider roasting dark in order to cover up the woodiness as being against the very ethos of Specialty Coffee. That said, the longer the coffee sits around the greater the decline in quality. One hopes that their customers will not notice, but is then almost saddened if they do not as it indicates that their customer base is less discerning than one would hope them to be. A daily cupping table full of old tasting coffees is enough to force anyone to rapidly lose any zeal associated with their job.
It was around this time that I was given the opportunity to steward my own coffee program. As a sort of promise to myself I said that the menu would always taste fresh. At the time I felt that this would of course have to be accomplished through careful buying as freezing an entire green coffee position seemed inconceivable; firstly because of the financial implications of owning your entire position in a freezer facility, but secondly (and more dauntingly) because I wasn’t exactly sure how to go about freezing coffee.
On the surface it sounds simple enough. We do, afterall, freeze things all the time in 21st century life. But the specifics surrounding freezing were enough to keep me concerned. George Howell was the only individual doing it on a large scale and, while I had some helpful conversations with George when I could bend his ear in an email or at a trade show, I felt bad taking advantage of his generosity and knowledge.
So, I started small. I purchased a small vacuum sealer and some appropriately-sized vacuum bags. I broke down a bag of coffee from Chiapas that I was worried would age quickly based on cupping an arrival sample, and I vacuum sealed the coffee into ten-pound increments. Absolutely terrified that I was missing some critical step, I stuck the coffee into a residential freezer and hoped for the best. A few days later, when checking on the coffee, I was absolutely certain that I destroyed it when I could see that the (formerly) green coffee was now ghostly-white. My mind went back and forth, deciding whether or not to remove the coffee then and there (maybe I could salvage it!?) or to leave it in its frozen catacomb. I ultimately decided to cross my fingers and leave it in the freezer.
A few months later, the unfrozen portion of the Chiapas lot was coming to an end. As I expected, the coffee was tasting worse for the wear. The ghostly-green coffee in the freezer was imprinted in my mind as a certain failure. I pulled the ten-pound vacuum sealed bricks from the freezer with a sense of utter defeat. To add to my despondency, many of the bricks had lost their vacuum. There was no question in my mind that this would present untold issues. I had planned to roast them the following day and assumed that the best thing to do was to let them thaw to room temperature before roasting them.
When I walked into the roastery the following morning, I was absolutely shocked to see green coffee that had a normal visual appearance. I was further surprised when the coffee roasted as I had expected it to. But, the true astonishment came into play the following day, when I tasted the coffee. Every single roast, whether from a bag in which the seal stayed intact or not, tasted as fresh as it did the day I put the coffee into the freezer.
I was by no means convinced that this meant freezing coffee was as simple as putting coffee into any old freezer. I was certain that I needed to nail down the exact ideal temperature, the exactly perfect vacuum sealing protocol, the ideal thawing time, etc. ad nauseum. That said, I was also convinced that I was exploring something that would forever change how I interacted with coffee.
Just a few short weeks after roasting those first frozen experiments, I placed my first full pallet of coffee into a freezer facility. I worked hard to figure out the ideal box size for the vacuum bags I was using. I carefully vacuum sealed 1,500 pounds of coffee in 20 pound units (my roasting batch size at that point). I then packed these twenty pound bricks into boxes, loaded them on a pallet and (literally) walked the pallet 0.6 miles (in the snow - a fitting gesture from the weather gods) to a freezer facility. Yes, that’s right, the roastery I was working with at the time was located less than a mile from a freezer facility. There was no question that the hands of fate wanted me to explore freezing coffee!
Needless to say, I have only gone deeper and deeper in my experimenting with and commitment to freezing coffee. As I helped launch another business a few years after my initial experiments with freezing, the decision was made early on to put a strong emphasis on coffee preservation. Within three years of that business launching, we were freezing 100% of our inventory (even decaf!). It became obvious to me that it was not only beneficial to do this for the most expensive coffees on our menu but also our blend components. This allowed us to go deeper into the relationships we felt strongly about. Rather than buying coffee for a few months, we were buying coffee for the entire year. Beyond this, we were able to always lean on the side of being a bit long as a little extra coffee in the freezer was a boon rather than a liability - as is the case with coffee stored at room temperature. For our more expensive coffees we were able to explore comparisons that I had never been able to taste before: the same producer’s coffee multiple years in a row, for example. Before freezing coffee, such an idea would have been absurd. Of course the previous year(s) coffees would taste like wood. However, with freezing, we could taste different harvest years side by side and have the coffee taste as fresh as the day we placed them in the freezer.
Over the past decade I have experimented with and explored many different variables when it comes to freezing coffee. I have launched successful freezing programs at two roasteries and consulted with a number of others as they explored this revolutionary preservation method. Rather than share what I have learned anecdotally, I would like to share a sort of bullet point list of best practices as it pertains to freezing.
The more time I spent working with frozen coffee, the more I realized that it is harder to mess up than one would assume. For years I tracked thawing times, thawing conditions (temperature, relative humidity), etc., etc. In the end, I found that there was very little that needed to be stressed over. If freezing green coffee is something you would like to incorporate into your company in a large way, I would simply recommend pulling the coffee that you will need for a week and planning on one-to-two days of thawing time before roasting. If you are pulling an entire pallet of coffee out of the freezer, you will be surprised by how long it takes to thaw the entire mass (up to two days). If you freeze in smaller units (roughly 5-10 pounds) and you are able to thaw them not stacked on each other, thawing can happen in a few hours. (A tip: if you are freezing in 5-10 pound increments, thaw on wire shelving. The wire shelving allows for good air circulation which is better for evaporation and even thawing. It also allows for the use of vertical space.)
If your coffee is frozen at an off-site facility that you receive deliveries from, the coffee will typically thaw en route! This is perfectly fine and normal.
But what about condensation?? Condensation on thawing coffee literally kept me up at night for a period of my life. I would take towels and wipe coffee down as it was thawing. I would stress about moisture inside of the bag. If a bag liner had a tear (something that happens more often than not), I would be sure to notate this on the production sample pulled to see if I noticed any difference in a blind evaluation. Never did I notice a thing.
Then, one day, the unthinkable happened. I was at a point in which I was having truck loads of coffee delivered directly from the warehouse to the freezer facility. I would then make weekly trips to the freezer to get the coffee needed for that week. I pulled a few bags of a coffee from Western Ethiopia that we had been roasting for months. As soon as I grabbed a corner of the bag to palletize it, I noticed it had no bag liner. It was a simple mistake by the dry mill: they forgot to include a bag liner for a few bags of the 100 bag lot. I took them back to the roastery and let them thaw for two days. I was fully expecting the coffee to have off-flavors. Lo and behold, it tasted absolutely fine. Obviously the coffee had condensation form on it while thawing and yet, there was no obvious damage. While I want to avoid wading into pseudo-science at all costs, I can only assume that the coffee was fine because the coffee is used too quickly for the issues that excess moisture typically presents to ever take hold. In short, I have never once noticed condensation causing problems on thawed green coffee - even the bags that had no liner! (To be clear, I am not suggesting that freezing without bag liners is a reasonable/viable option.)
One cardinal rule that I have found when it comes to freezing green coffee is that once coffee is thawed, it ages quite rapidly (relatively speaking). If you roast the coffee within two weeks of pulling it from the freezer, there is no risk of the coffee aging in that time (assuming the coffee had no age going into the freezer). In fact, I have found that coffees typically begin to show age four-to-six weeks after thawing. The two week window was a precautionary rule of thumb that I used.
I have also experimented fairly extensively with roasting frozen coffee and can report that it works incredibly well. That is right, directly from the freezer and into the roaster. I was always interested in doing this, but was terrified that it would be bad for my roasters. After a conversation with a mechanical engineer who was quite confident that it would cause no issues to either a Loring or a traditional cast iron drum roaster, I gave it a try - and never looked back. Roasting directly from the freezer for small batch, expensive coffees, added an incredible layer of consistency to my roasting protocol.
Packaging in the Freezer
In my early freezing days, I vacuum sealed every single pound of coffee I placed in the freezer. As the companies I was working with grew, this began to become burdensome. After some experimentation, I discovered that freezing in bag liners (Grain Pro or similar) was every bit as effective as freezing under vacuum. Not only did this save me a great deal of time, it reduced the amount of plastic in the world’s landfills.
If one wishes to break a bag down into batch size units - something I frequently did for more expensive coffees - you can use any moisture/oxygen barrier packaging to great success. Ten pounds of green coffee fits very well, for example, in a five pound bag intended for roasted coffee. There are a number of companies that sell these bags without one way valves. Simply fill the bag, push out any excess air and seal. These bricks of coffee stack neatly in cardboard boxes for long-term storage. Eventually, the extra plastic associated with the five pound bags began to wear on me. I ended up sourcing buckets with air-tight lids that have gaskets. This ended up being an excellent washable, stackable, and reusable option!
Temperature of Freezer
When I first started freezing green coffee, I was very concerned about the temperature the coffee was being held at. I had found some basic information on the internet that said the coffee should be held quite a bit lower than freezing. That said, after holding coffee for years in various freezers, I have found that any freezer that is consistently held below freezing temperatures seems to be sufficient for green coffee preservation. Of course, I feel some level of comfort when the freezer/facility is quite a bit below freezing. That said, I have no scientific proof or reason to believe that the lower temperatures are better as anything below freezing has performed the same in the finished product, as far as I can tell.
Does it Really Keep Coffee From Aging?
Absolutely, positively. I have conducted dozens of blind cuppings with the best cuppers I know, placing three, four, five year old coffee that was frozen, next to fresh crop coffee. No one (myself included) has ever been able to taste any meaningful or identifying difference in coffees that have been frozen when directly compared to those that have not been frozen. Now, to be clear, if a coffee had any age or was fading in any way, prior to going into the freezer, those flavors will, without question, be present when thawed and roasted.
But what about the carbon footprint associated with freezing coffee? Doesn’t the added emissions associated with this preservation method fly in the face of one of the purported goals of specialty coffee: to bring coffee to market in a way that is better for the environment?
Yes, to a certain degree that is true. In truth, it is something I have wrestled with through my journey. Ultimately, however, I do believe that this is an important step to carry us towards another goal (maybe the goal) of specialty coffee: to present coffee in such a way that raises it above commodity status and, by doing so, to create a market around the inherent value of the agricultural product as a unique epicurean experience whose flavors are influenced and dictated by the time, place, craft, and plant genetics associated with its production. If we cannot successfully execute upon this, Specialty Coffee will never grow beyond a white savior complex charity topic in which we ask people to pay more for coffee simply “out of the goodness of their hearts.” Our supply chains have so successfully made it possible for any number of agricultural products to get to our grocery shelves, tasting fresh, year-round. I believe it is time to extend this same possibility to coffee producers and to let them reap the benefits of doing so.
So, why write about this?
There are a number of reasons. Firstly, I am passionate about this topic and have spent the better part of the last decade working on ways to do it better. I enjoy talking about it and wanted to send an open invitation to anyone reading this who would like to discuss this topic further. Secondly, since before my time at Osito, Kyle Bellinger and I have often discussed ways we could incorporate freezing green coffee into our portfolio of services offered. As 2022 approaches, Kyle and I both see some small ways that we can begin to incorporate freezing green coffee into Osito’s business model. Furthermore, we continue to dream about big ways we could make this idea part of our DNA. While the future is yet to be written, one thing is certain: in the very short term, one can expect to see Osito begin to execute on these ideas. We hope you are interested in joining us on this journey!
- David Shaub Stallings