I'm a Coffee Roaster: Here's What You're Doing Wrong That's Ruining Your Coffee

The perfect cup of coffee is elusive. You can source the most wonderful beans in the world, roast them perfectly, grind and brew with expensive equipment, but it only takes doing one step incorrectly to render everything else useless.

The good news is by just educating yourself in this article, you can improve the coffee you make today without necessarily investing into expensive coffee equipment.

Here are the things I see many people doing wrong.

Don't grind more than you need
and before you need it

Remember the smell of a bag of ground coffee? Doesn't it smell wonderful? Did you also feel like it didn't taste nearly as good as it smelled?

The funny thing is, freshly roasted coffee doesn't have much of a smell at all on the first day. It's only after the gases have left and oxidation has begun that coffee begins to take on its characteristic smell and flavor. By the same process, letting this go on too long causes those flavors to wane, though the smells produced linger. This tricks us into believing a perfumy bag of ground coffee is going to taste delicious. In fact, it may be the result of stale grounds.

The best coffee is ground right before brewing, and only the amount you need for that brew. For this reason, prefer buying your beans whole and as recently roasted as possible.

Don't use a propeller grinder

I admit, this took me a long time to come around to. Why on earth would I need to spend on a good grinder. All it is doing is taking beans and crushing them into little pieces. How much better could a good grinder do this very simple task?

If you try this out yourself by tasting coffee ground in a conical burr grinder versus a cheap propeller one, you'll be hard pressed to deny there is a huge difference. The reasoning is all to do with extraction.

The more time a piece of coffee bean spends in hot water, the more the soluble components of it are extracted. There's a Goldilocks zone for this. Underextracted coffee is flat and weak. Overextracted coffee is overwhelmed by bitterness. This is why coffee grinds for a French press are large and tiny for an espresso. Think about how long the water stays in contact with the bean in each process.

Propeller grinders don't give you one size of grind to rule them all. It's actually worse than that. They give you all the sizes. That means you'll have pieces that are suitable for your brewing style mixed in with "fines" which will cause the coffee to over extract every time.

I prefer the Baratza line of grinders which can be easily maintained over time. An entry level model will set you back about $150 and you may be able to find it cheaper used.

If you can't spend on a good grinder, choose instead to buy smaller quantities of coffee and grind for immediate use in a grocery store. See my note about buying coffee in the grocery store later.

Don't measure your coffee by volume.

Like cake, coffee actually increases in volume after roasting. The amount of this increase differs from bean to bean and even between roasts. Making a great cup of coffee is also about finding out exactly how you prefer it. That means you'll need to find a way to be consistent from cup to cup.

If you're measuring the volume of beans or ground to use in each brew, such as by number of scoops as many do, you're not going to be very consistent cup to cup. The best way to maintain consistency is to find out your preferred coffee to water ratio. If you don't know this yet, start with the ratio 16:1 and experiment from there.

I recommend using the metric system for this because it makes everything so much easier. Remember that 1g of water is equal to 1ml. This is handy because you can weigh out, say 31.25g of coffee, zero the scale it's sitting on, and pour in water until you have 500g (500g = 16 x 31.25g)

Don't use boiling water

This is a common mistake the vast majority of us do. Coffee loses precious volatile flavors in boiling water. It's better to make your coffee in water no hotter than 96º C or about 205º F or "almost boiling."

I use a special kettle that keeps the water at a specific temperature while I'm gradually pouring into my pour over set up.

Don't use tap water

The coffee beverage is all about delicately dissolving solutes in water. Tap water is already saturated with different solutes, making it harder for new ones to dissolve and introduces unwanted flavors that clash with the coffee. Any impurities you can remove from the water you brew with will result in a better tasting cup.

Don't buy beans at the grocery store

We think of coffee beans as dead. They are dry, cooked, and kind of look like dirt when ground. However, it's really a mistake to think of them this way. The moment they are roasted, the flavors produced immediately start moving out. Coffee experts say roasted coffee is really only good for about three weeks. Personally, I never buy coffee roasted more than 1.5 weeks ago.

When roasted coffee is not used up during a certain period of time, it's sent to wholesalers like grocery stores and are not sent in with an expiration date. Many won't even tell you when they are roasted.

Even the fancier grocery stores will have more "premium" offerings. However it still has the same supply chain in front of it, only slightly different products. There is no one pulling month old coffee off the shelves. It's really not that different. A $50 bag of Kona coffee is a waste of money if the beans have gone stale  

As an alternative, some coffee shops will provide you with their own roasted coffee roasted fresh. You can even sign up for subscriptions like ours with no plastic and all compostable materials to get freshly roasted coffee delivered to you on a regular basis.

Don't percolate

I try not to step on people's toes regarding the tool you use to make your coffee, but this one is an exception. Never use a tool that percolates the coffee. Percolators constantly cycle the water over the grounds preventing you from having any control over extraction. The more your coffee percolates, the more bitter it gets and the more the delicious volatile flavors vanish. There are other tools you can use, but my most favorite is the pour over method.

Don't consume inconsistently

Let's talk about that coffee ratio again. All the tips in the world about making great coffee don't make a difference if you're not paying attention to your own palate. What tastes like a good cup to me won't necessarily be the same for you. The best way to dial this in is to try beans from different origins and find your perfect coffee ratio.

When buying beans from different origins, you'll want to buy single origin coffee, which lets you get a feel for how one coffee can taste different from one part of the world versus another.

Start your coffee ratio with 16:1 water:grounds by weight (by weight!). If that's too weak for you, try 15:1. If that's too strong, come back to 16 or try 17:1. The best way to do this in my opinion is with the pour over method, which gives you precise control over each step of the process.