There are some things in the world that we take as such certain truth that we rarely even think about them.
Gravity.
The sun rises in the morning and sets in the evening.
The Earth is a sphere (well… most of us agree on that one).
Similarly, there are some things when it comes to preparing coffee that have been drilled into our heads so many times that we often take these “facts” for granted.
Brew water temperature matters.
Coffee tastes best within a couple of weeks of roasting.
Fines migrate within a portafilter.
But what if everything we thought we knew was wrong?
If you were to discover that, say for instance, that perhaps fines DO NOT migrate; that your water temperature does NOT have to be 200F, or maybe even that you could pop open that two-month-old bag of beans without a worry in the world, would those revelations blow your fragile coffee, soaked mind?
Well, in the apt words of legendary Jurassic Park Chief Engineer, Ray Arnold:
“Hold on to your butts,”
because it’s time for some Coffee & Controversy.
Controversial Take 1 – “Brew temperature… has little impact on the sensory profile of drip brew coffee.”
Anyone who has been through a coffee brewing training in the last decade plus has likely been told that the ideal temperature range for brewing coffee is 195F – 205F. That, we have been told, is the range at which water is the most effective solvent to the sweet, tasty solute that is our coffee and that which will yield the most delicious cup.
Well, nerds, an October 2020 study published in Scientific Reports, titled “Brew temperature, at a fixed brew strength and extraction, has little impact on the sensory profile of drip brew coffee,” concludes that brew temperature at a fixed brew strength and extraction, has little impact on the sensory profile of drip brew coffee. Wild.
According to the study, when professional sensory experts were presented with samples of coffees brewed to pre-determined strength and extraction yield parameters – but with different temperatures – the judges were unable to detect flavor differences in samples brewed at different temperatures.
To achieve the same strength and extraction figures across samples brewed at different temperatures other variables were manipulated such as brew time and grind size.
Controversial Take 2 – “Either fines [don’t] migrate, or their migration [doesn’t] cause an issue.”
Think back to barista training once more.
Espresso Day this time.
Do you remember learning to grind, dose, and tamp?
You may have been told that one purpose of distributing and tamping well was to prevent fines (ultra-fine ground coffee particles) from “migrating” to the bottom of the portafilter and, thus, leading to channeling, flow-rate issues, or other problems.
This idea has been challenged recently by several different experiments that all seem to indicate something different.
In a Socratic Coffee experiment, they sifted coffee grounds, layered doses in layers of varying particle sizes in portafilters, and then examined the layers after pulling the shots.
Barista Hustle approached their experiment by tapping each portafilter 100 times before tamping and pulling shots, the thought being that while tapping, finer particles would work their way downward.
Towards Data Science set up an experiment where they layered fine chalk shavings on top of espresso doses to examine their rate of migration.
In each experiment, either no migration was observed or no discernible difference in channeling or shot quality were observed.
Controversial Take 3 – “A coffee that was of good quality when it was fresh will probably still be quite drinkable when it's a bit long in the tooth.”
“Coffee is a produce and has such has a finite period of freshness. We recommend consuming coffee within two weeks of being roasted…
TWO WEEKS OFF ROAST!!”
We’ve probably all been told this. It’s become all but a governing law of the Specialty Coffee universe but according to Sprudge interviews with three Specialty Coffee pros, perhaps it has attained that status undeservingly.
Let’s examine these three perspectives.
Myth: “Fresh is Best No Matter What”
Myth-Buster: Esther Shaw, of Coptic Light Coffee
Shaw’s is perhaps the least radical of these three perspectives, acknowledging that coffee requires a period to de-gas (expel gases built up inside the roasted coffee beans during the roasting process) before being brewed, while noting that this window may be longer than many believe it to be.
Perhaps the most interesting idea put forth by Shaw in the piece is the idea that the expansion of this “freshness window” might not be something new but rather an ongoing trend.
“’Interestingly, the recommended amount of rest time has changed since I started working in coffee,” says Shaw.’ When I first started close to 10 years ago, the standard seemed to be brew within 2-4 days and pull for espresso in 5-7 days after roast for the optimal taste experience. These days it seems to be closer to 10 days for brewing and anything from 14-28 days for espresso—sometimes even longer.’”
Myth: “Coffee Expires”
Myth-Buster: Sam Sabori, of Intelligentsia & Klaus Thomsen, of Coffee Collective
To be honest, this isn’t that much different than the first myth (what is a “best by” or “expiration” date but a freshness recommendation?) but let’s roll with it.
While it’s unlikely that many in the Speicalty Coffee industry think of a coffee “expiration date” in the same terms which they would products like dairy or meat which can make someone quite sick if consumed past the recommended dates.
Most think of it more like the “Best Before” date you see on a package of cereal.
Will it make you sick if you consume it past it’s date?
In most cases, unlikely.
But will it taste good?
That may be unlikely as well. But maybe it could taste fine?
The point at which coffee is “no good” may seem subjective but Sam Sabori, of Intelligentsia, and Klaus Thomsen, of Coffee Collective, told Sprudge that their companies have put in the work to try to make this process as objective – and as meangingful – as possible.
“’When we started the company we did a series of experiments because we wanted to see what is freshness and how does it affect the actual quality of the cup,’ says Thomsen. ‘We would store samples and take them out over time, and we were really interested in ‘what is the peak window of the coffee and how does it change?' We figured out that the degassing really does happen over quite a long time. It's very rapid in the beginning and then it slows down,” he continued. “We felt like for filter coffees it was best if we waited about a week, it would really peak, and we found that we actually had a really long window—you could wait two months and it would still taste fantastic,” says Thomsen. “After that you could still lose freshness, but if you ground fresh, we found that it's really nice up to about three months. After three months you are starting to lose quite a lot of freshness of flavor, so we didn't want retailers to have the bag and sell it on.’”
Myth: “All Coffee Packaging is Created Equal”
Myth-Buster: Klaus Thomsen of Coffee Collective
With the variety of coffee packaging observable on the market – ranging from the classic, stamped, brown, kraft paper bags of yesteryear to fancy, custom printed packaging that stand on their own as works of art - it would stand to reason that all of these products must perform well – or at least similarly… right?
Well, like in most things, let’s not go making any assumptions.
Coffee packaging actually plays a huge role in how fresh coffee stays both before and after you’ve opened the packaging and many roasting companies (not excluding KLLR) put a lot of time and energy into sourcing packaging that is both aestetically pleasing and able to maintain the freshness of the coffee.
Many roasters have come to different conclusions on what is ultimately the best packaging for roasted coffee, some even taking extra steps to those ends. According to Klaus Thomsen, nitrogen-flushing is the path Coffee Collective ultimately chose to pursue, stating:
“’Our experiments figured out that the best thing is to remove the oxygen, so we flushed with nitrogen, straight from the beginning, so there's none of that oxidation happening. So that means that your degassing can sort of happen on its own.’”
Controversial Take 4 – “Microwave Your Coffee”
We’ve got grinders that sell for thousands of dollars marketed on their ability to remain cool.
We’ve got grinders marketed on their ability to equilibrate their temperature.
We’ve read research papers declaring that frozen coffee beans grind most consistently.
And now we’ve got OG Specialty Coffee talking head telling to microwave our coffee.
Wut?
To clarify, we don’t mean the ol’ “my coffee is cold so I’m going to give it a zap to heat it back up,” trip.
Hoffman suggests that by microwaving the unground coffee beans before grinding, we can achieve a finer average grind particle size, and higher extractions.
Check out the video on his YouTube page, grab your portafilters, wipe the splattered queso off the roof of your microwave, and get ready to go.
The Takeaway
Let’s start by defining what the takeaway is not.
Don’t go taking any of these anecdotes as facts, don’t radically alter your café’s operating procedures, and don’t cop a snobby attitude when correcting your “less-educated” barista buddies.
The takeaway is that the rules are always changing.
Maybe there are no rules.
At the end of the day, we think it’s cool that people are trying new things and telling other’s about it.
Tried something new lately? Let us know about it!
