Freshness in Coffee and Science behind it's Ageing
Freshness as a concept has been at the heart of specialty coffee since its beginnings. It is one of the key parameters to control when we want to showcase exceptional specialty coffee products. The focus is on using the freshest roasted beans and brewing them as quickly possible. The definition of coffee freshness is to have original unimpaired qualities (i.e. Both Aroma and flavors).
Coffee is not a perishable product but a coffee older
than 1-2 months from the date of roasting will taste very flat and stale since
it has lost most of its aromatic compounds and flavors created during
roasting. The biggest destroyer of coffee freshness are sunlight, heat,
moisture and most important oxygen. If you keep your coffee beans/ground coffee
open in contact with air it will lead to oxidation and will lead to degradation
of aroma and flavor.
Coffee credits: corridor seven coffee roaster
Can coffee be too fresh?
When coffee is roasted a large number of chemical reactions happen which breaks down sugars and amino acids into carbon dioxide (CO2) which is trapped inside the coffee beans after roasting and slowly leaches out with time. This process is called degassing of coffee and is a lot quicker in the first few days and then gradually during the remainder period, Therefore it is suggested to rest coffee for few days after roasting which can range from 4-7 days in case of filter coffee and 7-15 days in case of espresso before it can be used. If a coffee is used just out of the roaster the excess CO2 can impede the water and interrupt the extraction resulting into flat tasting cup. If you have wondered what the small valve in your coffee bags is for, it is to allow the CO2 to escape slowly from the bag or else the pressure created from release of C02 can make your coffee bag explode. These valve are generally one way which allows escaping of C02 from the coffee bags without letting oxygen enter the bags and delay the oxidation process.
You can observe the amount of CO2 in your coffee by
looking at the bubbles formed during the blooming stage for filter coffee and
through the thick creamy layer of crema formed in an espresso shot. The more
the coffee is rested CO2 is released and less bubbles and crema will be formed,
Therefore it is suggested to let your coffee rest a little while after roasting
in order to extract the best flavors out of it. The amount and duration of
degassing is also impacted by the roast profile of the coffee, a darker roast
will create more C02 during roasting and will degas more quickly as compared to
a lighter roasted coffee.
Staling of Coffee
As said by James Hoffman in his book "The World
Atlas of Coffee", when coffee goes stale there are two main changes
happening to your coffee. The first is a slow but steady loss of aroma, the bag
of coffee which is more than a month old will probably not smell as good as the
bag of coffee that just arrived at your home from the roaster. This is because
with the release of CO2 in the bag some of the aromatic compounds which gives
coffee the flavor and smell is lost.
The second change that happens in coffee is staling due to oxygen and moisture. The contact of oxygen with coffee will lead to oxidization and will lead to creation of new flavors which are unpleasant most of the times. More the coffee is in contact with oxygen more flavor and original character will be lost resulting in a very stale or flat tasting coffee. Naturally your coffee beans have oils or lipids present on them while roasting and the contact of oxygen with them will lead to very unpleasant rancid tasting components that should be avoided in any coffee. Moisture and heat will increase the oxidation process and will degrade the coffee much faster as compared to one kept in a cooler environment. Coffee generally tends to lose its freshness after 4-6 weeks from roasting but can be varied depending upon different types of coffees.
Coffee storage
1. Coffee should be stored at room temperature and
preferably at a darker place. Storing coffee in a hot place will lead to faster
Oxidation since oxygen reacts much faster in a warmer environment.
2. Store them in an opaque, air-tight container at room temperature. Coffee beans are beautiful, but avoid transparent containers which will allow light to compromise the taste of your coffee. I prefer keeping my coffee in the original bags that it comes in from my roasters, according to me transferring them in a different container will suck out some of the flavor/aroma bites from the coffee present in the bag (one of my coffee myths). However you can always store your coffee in air tight container and do not forget to label them, because you need to know from which of the beautiful Indian estate is your coffee coming every time you brew.
3. Avoid humidity and therefore you should avoid freezing your coffee. There is a lot of debate over increase of Longevity of coffee beans by freezing them in the refrigerator, since coffee tends to stale slower on lower temperature and putting them in a refrigerator in sub-zero condition will slow down the staling process by months. But coffee beans are porous and will absorb smell and moisture of other items present in the refrigerator if not kept in vacuum sealed bags. Also there is a risk of condensation of excess moisture once the coffee is taken out from the freezer and will accelerate the ageing process.
4. Buy the right amount of coffee every time, It is always advisable to buy in small quantity for immediate consumption (i.e. for the next 4-5 weeks) rather than buying a big bag of coffee which you will not consume for months and will get stale in the process. Therefore always buy the right amount of coffee to ensure maximum freshness every time.
Lastly as most of the things in coffee, Freshness is also very subjective and can depend on a lot of factors ranging from the brewing type, processing method, roast profile and personal preference. Therefore some coffees may take longer time to show their full potential and may not taste stale after 2 months as well. Therefore explore what works best for you and your coffee and keep trying new coffees, this is what makes coffee so interesting and intriguing.
In conclusion always try to buy freshly roasted coffee directly from your local roaster and be part of the budding coffee community in India. Leaving below the links of some of my favorite coffee roasters in the country (the list is not exhaustive):
https://bluetokaicoffee.com/collections/coffee
https://corridorseven.coffee/collections/all
https://kcroasters.com/collections/indian-coffee
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