Why is My Coffee Bitter? (9 Reasons)

While coffee has long been associated as being a bitter drink, when coffee is made right its bitterness should not be the dominant flavor when you drink it. A good cup can have bitter elements, but as well as that it can have woody, spicy or even chocolatey notes.

Extraction is the process that pulls solubles and aromas out of coffee grounds into water. These flavor compounds than dissolve into the water to give us our desired cup of coffee. The problem is that over extraction can expose bitter compounds to the water, so the key is to only extract up until the point.

There are a few variables and home brewing mistakes that can lead to over extraction, ultimately affected taste. So here are nine reasons why your coffee is bitter.


#1. Stale Beans

The freshness lifespan of coffee beans is actually quite short, and from their roast date you don’t have long to use them before they go stale.

In general, whole coffee beans stay fresh for about 3 weeks after roasting. When buying them I always recommend opting for beans no older than one week old, giving you two weeks in which to use them.

After this three-week period, the oils and sugars in the beans start to escape, leaving you with a bitter-tasting bean.


#2. Dark Roast

Some dark roasts can have quite an overwhelming bitter taste. Their longer roasting time can result in lower acid content, which means less aroma and a more bitter flavor profile.

Instead, try to go for medium roast when choosing your coffee. Also if you’re worried about weak caffeine content then don’t be: Lighter roasts actually tend to have higher caffeine content than dark varieties.

Learn the differences between arabica and robusta beans.


#3. Pre-Ground Coffee

Pre-ground coffee offers people without a grinder a great means of accessing good coffee without having to stock up on more equipment. The downside of this however is that the grounds that you do use are old have been exposed, aging them.

See, once beans are roasted their aging process begins. However, once they are ground then this process speeds up significantly. And while it wouldn’t be fair to say that pre-ground coffee is bad or unusable, it will be prone to turning bitter far quicker than their whole bean counterparts. In fact, in as a little as 24 hours ground coffee can start to assume a bitter flavor profile.

It might not be what you want to hear, but I always recommend getting whole bean roasted coffee and make that extra investment into a grinder. Buying one of these isn’t actually that expensive, and is certainly worth it for what you get in return in your cup.


#4. Grounds are too fine

Coffee grinding is often a balancing act in finding the right grind size for your chosen brewing method. If they’re too coarse then your coffee will under extract and be too weak and sour; and if they’re too fine then they’ll over extract.

Often it’s the latter that happens, especially with manual blade grinders, and doing this can mean that the contact time between your water and grounds is too long. This results in a bitter flavor profile in your coffee.

The grind size you need will completely depend on your chosen brewing method. As a rough guide, fine grounds are for espresso, and coarse grounds are for French press. For a more detailed overview, check out my guide to grind size here.


#5. Grounds steeping too long

Another determining factor in over extraction is overly long contact time. For methods like pour-over this can be easily solved through good grind size, but for french press steeping time is much more down to you. It’s crucial you don’t leave your grounds submerged for more than 3-4 minutes. Anything over this amount of time will leave your coffee prone to over extracting and turning bitter.

This is particularly common with French press because even when people have used the plunger, they leave the coffee in the press where it continues to extract. When they then go to serve a second cup from the press, it’s using overly extracted coffee, making this second cup far more bitter than the first.

To get around this, I recommend using a carafe to transfer all your brewed coffee to once you have used the plunger.


#6. You’re using the wrong brewing method

Brewing methods that require a very fine grind, like espresso or French press, naturally yield bitter results. If you brew coffee at home then go for pour over brewing.

Pour over methods tend to require a medium grind, which has more coarse particles. This results a far deeper, less bitter blend.


#7. Your water is too hot

It’s widely agreed that the optimal brewing temperature is between 195°F and 205°F degrees. This is usually the temperature your water sits at about two minutes after being boiled.

If you add the water just as it’s boiled it’ll be overly active and extract the bitter compounds in the grounds.


#8. Your equipment is dirty

An often overlooked factor in bitter coffee is equipment cleanliness. If your machine or equipment has leftover coffee from your previous brews in it then this will contribute to the problem. These coffee particles will have aged and turned stale, and can significantly impact the taste of your coffee. Try to keep your equipment clean by rinsing its washable parts regularly, perhaps even after every use.


#9. You are using instant coffee

It can be tempting to go for instant as it’s cheap and not as time-consuming as coffee beans or grounds, but it really is a case of you get what you pay for with instant. It can taste incredibly bland or bitter due to the preservatives and additives it contains. Also, it’s almost always made with very low quality coffee beans. All of this combines to give you a poor-quality cup that sits firmly on the bitter side.

If you are yet to make the leap, I urge you to make the change to coffee grounds. You’ll never look back.

Need a quick fix to remedy your bitter coffee? Here are three quick ways to try to save your cup.

  1. Add salt. The sodium chloride in salt can bring out the sodium in coffee, which in turn makes it taste less bitter. Common table or kosher salt can go a long way to cut down on nasty bitterness. Don’t worry, adding a small amount of salt won’t give you a salty tasting coffee or harm any of the other flavors in your cup.
  2. Add milk or cream. If you drink your coffee black then this might not be for you, but if you tend to regularly drink your coffee with cream or milk then adding some to your cup will help to cut down the bitterness. The fat content in cream can counteract the bitter compounds in the coffee to edge you towards a more neutral taste.
  3. Add sugar. Sweetness can work well to counteract bitterness. A teaspoon should be enough to make the flavor of the coffee more pleasant. This works well with either white sugar or brown, although white tends to have fewer additives so that might work better to quell the impact of bitter compounds.

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