⚛️ Re: The Chemistry of Coffee Extraction

This last technical summer series is dedicated to understanding coffee brewing in more depth. This will enable you to find your own “perfect brew” and more easily adapt to any potential new brewing method, or new bean (yes, we’re working on another limited edition Honey micro-lot coming your way in September 😉).

We define brewing or “coffee extraction”, as the process of transferring aromas, flavors, and textural components from the coffee grounds into your brewed cup of coffee. Your freshly roasted coffee grounds will always contain two types of compounds: soluble (typically desirable) and insoluble (typically less desirable).

Soluble compounds include both soluble aromas (in gas form) and soluble flavors (in liquid form). Since soluble aromas are not -strictly speaking- “dissolved” in water, they are lost over time, as your cup of coffee cools down- which is one of the primary reasons your coffee tastes a little different as it cools! Yet, all soluble flavors and textural components will remain unchanged as your coffee cools down, which is also why professionals typically judge both flavor and textural attributes of a particular coffee only after the brew has had a chance to cool down.

Insoluble compounds include oils (which are non-polar, so they won’t dissolve in water, and will float on your cup’s surface, due to their lower density), and fines (which are more noticeable when you are not brewing using a paper filter, i.e. on French Press or any method using a metal filter). Fines are simply very small grinds that are inevitably produced by your grinder (even the best ones!), as some particles get further degraded by the heat and movement of the burrs produced during grinding. The presence of both oils and some fines - or insoluble solids - tends to make your cup more viscous, or “full bodied”, yet excess fines may make your coffee feel gritty. If you find that fines and oils are something you don’t particularly enjoy, using a paper filter will largely eliminate both. In general, the thicker your filter, the less fines and oils you can expect in your final brew (yet, you should keep in mind you'll also be sacrificing some of your cup’s texture or “body”).

Hope you enjoyed this little coffee chemistry lesson… and that it helps you continue Brewing Greatness in the world with us! Always grateful for you,

Jolian & Lisbeth

P.S. We’ll be roasting Mondays and Thursdays for the next two weeks, since the Lakeland farmer’s market is closed in August and it is the only month of the year that we can offer our amazing small team some (very well deserved) weekends off! We’ll be back to our Mon/Weds/Fri roasts the week of Aug 27. Thank you for helping us make our Ethos a reality every single day… we LOVE roasting for you!

RE: FRESHNESS! | Why it matters? How can you keep your coffee fresh?

Summer is here! And we wanted to welcome it by launching our "RE:" Summer Series - i.e. posts intended to increase your coffee knowledge and bring your coffee experience to a whole new level! They're inspired by questions we frequently get... and we hope you'll help us keep them relevant and interesting by suggesting new topics!

This first one is on a topic we're particularly obsessed about - FRESHNESS! It is perhaps one of the most important quality attributes in coffee, and a major predictor of both aroma and flavor intensity! Why? Because the chemical reactions responsible for coffee aroma and flavor are the same that happen in baking (ever compared a freshly baked loaf of bread with one that's been sitting in your pantry for a week?) - the Maillard reaction (between amino acids and reducing sugars) and Caramelization (the thermal breakdown of sugar). It is these two 'non-enzymatic browning' reactions that transform green coffee components into delicious nutty, chocolatey, 'freshly roasted' aromas & flavors in our coffee beans! We've included links to their Wikipedia pages, for those who'd like to have some fun looking at the chemistry! (I actually had to memorize all the chemical steps for both of these for my PhD Qualifying Exams... they're THAT important... and also responsible for flavor in any food product that's baked, cooked, roasted, browned, dried, etc.... but I digress!).

Now, the tricky part is that all of the aromas (which are also key to certain flavors) formed in these reactions are volatile... which means they're lost over time. In roasted coffee, this loss is exacerbated by the natural "de-gassing" process, i.e. the release of carbon dioxide that has been trapped within the bean's cell structures during the last roasting stages, and slowly released for months after roasting. And while there's nothing we can do to stop this... there are some ways you can keep your coffee fresh longer!

The first is to BUY FRESH! - using your beans within a month of the roasting date will always give you the best experience! You can expect mild flavor changes after 6-8 weeks, and pronounced changes after 4-5 months (yet we hope your beans won't ever last you that long!). The second is to  GRIND FRESH - keeping your coffee beans "whole" means less surface area will be exposed to air...  leaving those delicious aromas "trapped" inside the beans for much longer! And the third is to KEEP COOL (but not in the fridge!) - keeping your beans in a cool (air conditioned), dark place (i.e. your pantry) and in a tightly sealed bag (i.e. the bag we ship to you is specially designed to keep your coffee fresh... only make sure the zipper is always tightly sealed!) will slow down de-gassing, and protect against flavor oxidation! Placing your coffee bag inside an airtight container will also provide some extra protection! Please don't place in the fridge or the freezer - as this will accelerate the de-gassing process (and your beans may 'absorb' some of the aromas/flavors of the other foods in your fridge).

Thank you so much for reading... we hope this was interesting & helpful... and please email us if you have any ideas/questions for our next "RE:" post!

Lisbeth

PS. Quick update on the R15 roaster... we finally got the electrical upgrade project approved, and the new panel was installed on our building last Friday... and are expecting Lakeland Electric to connect our new power as soon as this week!!!