We are often asked by many of our coffee drinking customers: is it better to buy whole bean coffee or have the coffee ground at the store? We always answer with an emphatic 'Whole Bean Coffee'! But why is the roasted whole coffee bean a better choice than getting the coffee freshly ground at the point of purchase? After all, it's less work to have your Barista grind coffee for you.
To answer this question, one must first understand what makes coffee go stale.
Oxidation is a chemical reaction in which electrons from one substance are lost to its oxidizer (a more electron friendly substance). This is a very powerful chemical reaction, for example iron exposed to air will rust, causing the metal to get brittle and damaged. Rusting takes place over a long period of time as its oxidation processes is slow. On the other hand coffee oxidizes fast!
Oxidation changes the chemical makeup of coffee and is one of the key factors in creating stale coffee.
This is where surface area comes into play. The larger the surface area of a substance undergoing oxidation the faster the oxidation process. When whole bean coffee is ground the amount of surface area exposed for one ground coffee bean increases from a little to a lot! As the picture shows :)
Ground coffee will go stale and its flavor will begin to decline rapidly within about 5-15 minutes of being ground.
This is why we in our cafe live by this coffee brewing mantra: 'grind immediately before you brew'. We take this seriously! The fastest way to create bad coffee is by grinding it far in advance. One of the single most important things to do in order to increase the quality of the coffee you drink is to 'grind right before brewing'. Even your expensive Kona Coffee or Blue Mountain Coffee will not stand up to the rigors of oxidation.
If you're a Barista in a high volume coffee shop you may be thinking that grinding immediately before brewing would kill productivity while those fancy coffee drink orders come flying in. But really, some ziplock bags filled with pre-weighed out coffee will be all you need to meet the crowd's demands. Just dump the pre-bagged coffee beans into the bulk grinder right before brewing. Side note, coffee weight to water ratio will be a discussion for another day.
So, when purchasing coffee for home, make sure to grind your coffee right before you brew it. Yes, this might be a little more inconvenient, but hey you call yourself a coffee drinker don't you?
This is the first in a series of fine coffee educational posts that we plan to turn into a 'Learn Coffee' reference library on our main coffee shop website.
Roast Coffee & Tea Trading Company is a coffee micro-roaster and fine tea purveyor located in the heart of Patchogue on Long Island. The trading company sells coffee direct to customers online, provides full service wholesale accounts on Long Island and operates a cafe in Patchogue.
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Published on Nov 20, 2012 by Evan Closson.