The bitter reality of brewing coffee at home

Updated: Sep 3, 2021

So, you got this whiz bang bag of coffee from your local roaster or store, paid a decent price for it, went home, got all the brewing apparatus ready, brewed your coffee and upon the first sip you go:

"Holy Molly - this coffee is sh***ockinly bitter!"

Well, we've all been there (I think). I know I have in the past.

The reality is that bitterness, whish it or not, is part of coffee - literally, and here is the culprit:


Which is also known by its alias - "Caffeine". And it's responsible for giving you alertness and also the shakes if you have too much of it.

Caffeine is a compound that some plants such as the coffee plant produce to ward off insects and other predators - and it even reduces the growth of other plants (weeds) in the surroundings. It's a defense mechanism. But caffeine isn't exclusive to coffee - other plants have it too, like cacao and some tea plants. I'm sure there are plenty of other plants that produce caffeine out there.

And caffeine is bitter. The more caffeine you extract in your coffee, the more bitter it will taste. You are probably getting the gist now.

The trick with every brew method (or if you prefer you can say coffee making) is to be able to extract the right amount of flavour compounds and caffeine in your cup so you are able to enjoy the different flavours that come from the different origins and different coffee processing types without excessive bitterness and other unpleasurable tastes. And the way you go about it varies depending on how you make your coffee.

Now, I'll try to be not too nerdy about this and summarise as much as I can, which is a challenge for me - I always choose the longest and more convoluted way to explain things (so I'm told).

Caffeine will dissolve in the water you're using to make your coffee and essentially you have to control that dissolution if you want a less bitter coffee. Think about the points below:

  • The longer you keep your coffee in contact with the water, the more caffeine you'll extract and more bitter it will tend be.

  • The hotter the water, the more caffeine will be dissolved (heat speeds up the process).

  • The finer the coffee grounds, the easier for the caffeine to dissolve in water

  • The darker the roast, the more soluble caffeine will be, which will make it easier for the caffeine to dissolve in the water.

There are other factors - for example some coffees have more caffeine than others - Robusta coffee has more caffeine than Arabica. But if you reading this I assume you would be drinking mainly Specialty coffee, and therefore Arabica.

But what can you do to ensure your coffee is sweet and not bitter? Remember the 4 points I mentioned above? Well, you have to control them as much as you can and the way you'll do that will depend on what type of coffee you are making (brewing method).

A point worth noting is that the same process that dissolves the caffeine into the water will also dissolve the other flavours you after so you have mindful of that.

Below are some tricks you can do at home to improve the way you brew your coffee and it's flavour.

The Mocha Pot or Stove Top

The Mocha Pots are notorious for making strong and bitter coffee. I, myself find it very hard to brew a sweet coffee with a mocha pot. I guess the main issues come from the fact that it is very hard to control what's going on in the extraction with a Mocha Pot.

Things that normally happen with a mocha pot when you are brewing with it are related to heat:

  • The pot itself gets too hot and continues hot after you turn the stove off

  • The coffee grounds are exposed to a lot of heat from the surface of the pot and for too long

The result normally is:

  • Bitter and strong coffee (it's actually mainly burned coffee I would say)

There are a couple of things that James Hoffmann (World Barista Champion 2007) suggests to be able to minimise the issue:

  1. Pre-heat the water - boil it with a kettle , pour it into the chamber and then do the rest as per normal - be careful not to burn yourself when you are screwing the top to the bottom part of the mocha pot. Use a cloth or something to hold the bottom part with the boiled water.

  2. Once the coffee is done, quickly remove the mocha pot from the stove and pour cold water onto the outside of the mocha pot to cool it down.

  3. This third is actually what found myself works for me - I grind the coffee coarser - meaning a bit finer than for filtered coffee, but nowhere as fine as a normal espresso.

  4. Pour the coffee as soon as you finish brewing it - don't leave it sitting there in the mocha pot.

  5. If you are still getting bitter coffee, try also a lighter roasted coffee, but the trade off will be an increase in acidity.

The Plunger or French Press

The Plunger is very common in households in Australia and is a very simple and inexpensive brewer that can give you a nice, heavy bodied cup of coffee. All you need is the plunger, hot water and coffee grounds.

The plunger will brew the coffee by infusing it, which means the hot water will sit there in contact with the grounds for some time and as we already learned, it will be pulling caffeine from the grounds by the millisecond.

I have 3 tips for a better plunger coffee:

  1. We have to limit or reduce the time we are infusing. My suggestion is 2 minutes and you have to stop that love affair between the water and the coffee or a bitter baby will be born in your cup. Do that by plunging as normal and pouring all the coffee into the cup. You can also limit the extraction after 2 minutes by removing the grounds that sit on top of the water using 2 spoons before you plunge, which can be a bit messy.

  2. Remember that finer coffee extracts quicker? There you go - grind your coffee on the coarser side and test the grind size until you find the right setting for your taste.

  3. A lighter roasted coffee will help as well if your coffee is still tasting a bit strong and bitter.

The Espresso Machine

Things can get bitter between you and your home espresso machine sometimes. That's normal, but as with any relationship you have to work on the issues and you'll be able to see how sweet that relationship can be :-).

The relationship parallel works really well in this case - you have to reach the sweet spot - if not you might end up with either a sour coffee or a bitter coffee - literally.

The rule of thumb is:

  • You under extract your coffee, you get sour coffee

  • You over extract your coffee, you get bitter coffee

If you are getting bitter coffee with your expresso machine you are most likely over-extracting , so try the following:

  1. Make sure you get your your desired extraction rate in 20 to 30 seconds. A good start is to make it about 1:2 (let's say 18g of ground coffee in the basket with a yield of 36g of liquid in the cup) in 20 to 30 seconds. If takes longer than that to achieve 36g, your coffee is likely to turn up on the bitter side. You might need a scale for this (obviously). : )

  2. Grind your coffee a bit coarser and try again, or

  3. Tamp the coffee more lightly, or

  4. Decrease the amount of coffee in the basket, or

  5. A combination of the above, although I think to start with, try to change only one of variables at a time. The easiest is the grind setting and you keep everything else the same.

Other things that will help you with the quality of you cup at home are to make sure you run some hot water through the brew head to bring it up to the temperature it needs to be before you extract your coffee. You can take that opportunity to also warm up the group handle basket under that hot water. This will prevent heat loss during the brewing process, which affects the brewing quality.

Hopefully with these steps you'll be able get better cup of coffee instead of a bitter cup of coffee.

You'll notice I haven't covered other methods, such as filtered coffee as they normally result in a less bitter coffee.

But if you're having trouble getting bitter coffee and the tricks I gave you aren't helping, please reach out and I'll do my best to help you.

-~-~-~-~-ENJOY -~-~-~-~-

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