Brewing coffee isn't rocket science. Fundamentally, it's the addition of hot water to coffee grounds and extracting flavours in the process.
However, controlling the amount of flavours that you extract can get pretty complicated. Over-extraction results in bitterness and the coffee often tastes diluted, whereas under-extraction is most easily identified by sourness (not to be confused with acidity) in the coffee. Finding the optimal balance of flavours is what baristas strive to do every day and we will dedicate a series of blog posts to understanding extraction in the near future.
Thankfully, there are a few quick tips that every budding home-barista can use to improve the quality of their coffee immediately:
1. Use fresh beans
This cannot be emphasized enough - fresh coffee beans make a world of difference as compared to supermarket coffee. Pro tip: look out for the "roasted on" date on the packaging. You want to buy only coffee beans that are roasted no more than 7-10 days ago. If a pack of coffee shows a "use by" date instead, usually seen in supermarkets and commercialised coffee chains, we'd recommend to avoid it like the plague. This is also why we have a promise to our subscribers that they will receive their beans no later than 10 days from the date of roasting.
2. Grind on demand
Pre-ground coffee is a big no-no and there's a good reason for that. Coffee loses its flavour within a couple of minutes from grinding. If you've been to any specialty coffee shops, you'll realise all of them grind the coffee beans only after you've placed your orders. Thus, buying the freshest beans and getting the store to grind them for you before bringing home won't do any justice to the coffee. Burr hand grinders are an affordable and quick way to get freshly ground coffee whenever you want it.
3. Water temperature matters
Water temperature affects the extraction process. The higher the temperature, the faster the extraction. If you don't have a thermometer to measure the water temperature, bring the kettle to a boil and then let it cool for 4-5 minutes. We also found that the fresher your coffee is, the cooler your water should be. Generally, 87-93C works well for most pourover and filter coffees. Pro tip: boil some extra water to warm your equipment and cups beforehand.
4. Know your coffee:water ratio
Most coffee enthusiasts would tell you that they measure the amount of coffee and water they use right down to the exact one decimal place. This is also why we provide the exact brewing parameters for all the coffees we feature. Using the right ratio will ensure a consistent cup each time you brew. Different coffees also require different ratios to extract the optimal combination of flavours.
5. Grind size is critical to fine-tuning your brew
As a general rule of thumb, if your cup of coffee tastes overly bitter, use a coarser grind size whilst keeping the rest of the variables constant. Likewise, if it tastes sour, use a finer grind size and try again. The size of the coffee grounds determine the surface area exposed to the water, which means a finer grind size results in more extraction - akin to how icing sugar would dissolve much faster in water than granulated sugar.
Making coffee is an experimental process. By understanding how different variables influence the taste of your coffee, you'll be able to tweak the process to get your favourite brew in no time. Enjoy!