0601_grinder

Grinder - The First Step to Great Cup After Cup

Question: Why is the coffee brewed in the cafe always tastes and smells better than the same coffee brewed at home? Or is it
possible to make nice coffee by ourselves every time and even better than the coffee brewed in the cafe?

Recall this - You bought a tin of the world most popular coffee ground packaged with pressurized inert gas that not only
guarantee prolonged shelf life but also provide an 'aging' effect with improved quality in terms of body and aroma. When you
opened the tin, the sudden gush of the best aroma fills the room, reaffirming the quality of coffee you've gotten. Then, you
dosed, packed, tamped and pulled the god shot - a reddish brown, tiger-stripped thick espresso ooze from the spout into the
demitasse, and for a moment, formed a shot full of crema. Perfect!

This is a typical scene and experience that repeats itself every time we open the pack of coffee ground for the first time and
make the first cup. Soon after, we will notice that the aroma starts to lessen, the espresso flows faster to the extent of gushing
out, and the final cup is filled with a thin layer of crema or worst still, none. Did we do anything wrong? Probably yes, if you are
using a manual or semi-automatic espresso machine. Such scenario happens not only to espresso making, but also with any
other coffee making method. Though there are many factors and variables affecting the quality of the coffee or espresso, one
key reason behind this deteriorating effect other than our skills is the freshness of the coffee grounds.

As a general rule of thumb, a pack of coffee whole beans can last between 1 to 2 weeks in terms of freshness, assuming that
the beans are stored in vacuum-sealed or air-tight containers once the package is opened. This is because coffee beans,
once roasted, will start to degas, a process when carbon dioxide, formed during roasting, is released together with the
aromatic volatiles at an initial increasing rate with a subsequent gradual slowdown. Here, the coffee beans start to lose its
aroma. And when the degassing process slows down, oxidation kicks in to stale the coffee. The longer we can hold on to slow
down the degassing process, we longer the coffee bean will last. Just like when someone tries to hold his breath in the water
longer, the faster he will grasp for air when he's out of the water. Similarly, coffee beans continue to degas even in the air-tight
container, and the pressure build-up in conjunction with the increase in concentration of the carbon dioxide will accelerate the
lost of aromatic compounds once the lid is open. That explains why our coffee deteriorates cup after cup with the same pack of
coffee beans, after the package is open.

This phenomena is amplified when the coffee comes in ground form. Keeping the coffee in bean form preserves the flavor and
aroma as long as possible up to 2 weeks. By grinding the beans, the cell walls of the beans are broken down into chunks and
flakes, or worst case almost powdery (ie. espresso or Turkish grind) that literally and physically accelerate the degassing
process. Coffee grounds, when exposed to air, will lose its aroma and flavor within 10-20 seconds. Imagine a container filled
with a pack of 250 grams of coffee grounds capable of giving 12 servings of 2 cups each time. When we open and close the
container to scoop out the grounds, we are exposing the grounds in the container to oxidation. Even within a few seconds,
fresh round of air goes into the container and oxidation continues after the container is sealed/closed. Remember the scene
when we first open the package to savor the strong aroma and subsequently the smell gets lesser and lesser? The aroma in
the container is slower displaced by air - the ultimate enemy of coffee. Compared to a container filled with whole beans, it is no
wonder that the whole beans can hold on to the aroma and flavor much longer.

So how does the coffee in the cafes or restaurants fair in terms of maintaining the freshness of coffee. Compared to home
users, cafe operators have the advantage of faster turnaround and replenishment. A pack of 500 grams to 1 kilogram of coffee
beans can be consumed within a day or 2, leaving minimum exposure of coffee to oxidation. Given that most operators grind
their coffee beans just before brewing, this further reduces the chance of having stale coffee.* Regardless of the sales volume,
most operators will want to maintain minimum supply of beans on a weekly basis for the same reason. Delaying the grinding
step to the instant of brewing is the first key point and prerequisite to making great coffee, cup after cup.

So, the next step is the choice of coffee grinder. The purpose of grinding is to increase the surface area of the roasted coffee
so as to facilitate the extraction of coffee flavor by dissolving the soluble compounds. In order to ensure consistent extraction
for a particular brewing method, the coffee grounds should be of uniform size so that water will flow through at an even rate
across the brewing surface both breadth and depth -wise. This is where the different types of grinders serve the different
demands of the consumers. A simple and most economical blade-type grinder whacks through the beans to break them into
small pieces of varying sizes. Though commonly found in most electrical appliances shops, it is not the recommended grinder
if you plan to get one. One should get the burr grinder instead. Read more about the different burr grinders and the features
that produce the best coffee grounds in our article, "Choosing the Right Coffee Grinder". Apart from producing uniform sized
grounds, another main criteria of a good grinder is the ability to minimize heat dissipation that will escalate degassing effect,
and to minimize the static that will create lumps of coffee grounds, leading to uneven extraction.

Once you have pampered yourself with a good grinder and see the difference it makes in the cup, do not forget about the
remaining coffee beans that you will consume later on. Just as we have repeatedly emphasized on the nature of roasted
beans degas and the negative impact of oxidation, we have to make sure that the coffee beans are well kept in the best
condition to minimize the lost of flavor and aroma. The easiest way is to store them in an airtight container to prevent air from
getting into the container to further oxidize the roasted beans. This easy way comes with a problem, that is, whenever we open
the container to scoop out the required amount of beans to make coffee, the air and aroma in the container will be displaced
resulting in oxidation of the remaining beans. So it is recommended to have a small instead of big airtight container. Ideally,
the roasted beans should have minimum contact with the air. So, the best storage solution for roasted coffee beans is to store
the beans in vacuum-sealed container. Here, air is sucked out using a suction pump that also served to seal the cover to the
container.

To summarize, follow below steps and you will be able to realize and enjoy the full potential of your favorite coffee, cup after cup.

Keep as small supply as possible of roasted coffee beans, to last, if possible only a week
Invest in a good doserless grinder that offers crushing and shearing effect to precise grind size according to the
brewing method, with minimum static and heat dissipation.
Delay grinding the beans until brew time
Store the remaining coffee beans in an air-tight, or preferably, vacuum-sealed container that minimizes the air content
leading to oxidation.

So, back to the question on whether we can make good coffee, cup after cup? The answer is a definite yes, if we can invest in a
good coffee grinder, and follow the above mentioned key points. For a home user, this basically defines a constant in the
formula of making great coffee, even before we start the brewing process.

To conclude, great coffee can be made out of a few-bucks brewer but it can never come from a lousy grinder.

* There is an exception in most specialty coffee cafes that serve both espresso-based beverages and brewed coffee, in terms
of the freshness of the coffee beans used. As mentioned, most cafes have at least 1 grinder for their regular espresso blend
used in all espresso-based beverages. When it comes to brewed coffee (where you can truly appreciate the taste of single
origin coffee) using either vacuum brewer or French press, however, you will not find the barista grinding the coffee beans
using the same grinder. Note that coffee made from airpots and pourover systems also suffer in terms of the end cup quality.
In most cases (or all cases where I've seen in all cafes in Singapore) the barista will use pre-ground coffee instead, which is
rather ironic or a shame. For economic reason and the relatively lower consumption of brew coffee compared to espresso-
based coffee, operators choose the easy way out without giving brew coffee its due treatment. This is where you can definitely
brew much better coffee at home than the cafes if you have a good coffee grinder.

Article written on 26 August 2006.