As you continue on your coffee journey, you may experience a puzzling roadblock: you order a coffee at your favorite local shop or roaster and love the way it tastes. Determined to enjoy this coffee every morning, you buy a bag fresh off the shelf and take it home with you. Using your favorite brewing method and your trusty Baratza grinder, you follow a recommended recipe. Then, with great anticipation, you take the first sip and are sorely disappointed – the coffee doesn’t taste at all like it did at the shop. In fact, maybe it tastes not good at all.

We’ve all been there, believe us, it’s understandably confusing. Let’s take away some of the mystery around why coffee tastes great sometimes, and not so great other times.

“The first, biggest step in quality coffee at home is quality coffee itself!”

There are an awful lot of variables in the brewing process (a.k.a. extraction) and it’s almost impossible to stay on top of all of them – though we listed five important factors to focus on in a previous post. Let’s quickly recap the three big ones.

The first, biggest step in quality coffee at home is quality coffee itself! After all, coffee is the main point of all this, so it’s important that the coffee you have is coffee you like!

The second big step in quality coffee at home is the grinder. Fresh ground coffee is much better for flavor in the cup, and a quality grinder gives you that along with repeatability and consistency in the grind. Your grinder will also allow you to control some taste results, as you’ll read further down.

A great third step is finding quality brewing water. Coffee is actually 98% water, so it can make a big difference in your brew if the water you use is less than ideal for extraction. Fresh out of the tap, water in most of the United States is clean and great to drink, but it likely isn’t ideal for brewing coffee. Simply using a counter-top water filter that you can find at a local department store will really up the quality of your coffee with minimal cost or effort.

With those three steps behind you, exceptional coffee quality is just around the corner! To absolutely nail it, we need to use our most powerful tool in evaluating coffee quality: our sense of taste! Let’s focus on how to use your sense of taste – or your palate – to determine what’s wrong with the brew. The two most common culprits behind less than stellar coffee narrow down to concentration and extraction. Let’s learn what each of these taste like.

Concentration is a term we use to describe the “strength” of coffee, generally speaking. Extraction is a measure of what we take out of the coffee that we’re brewing.

 

In short, Concentration is often expressed as a ratio of dry coffee grounds to water (for example, 1:17 means one gram of coffee for every 17 grams or milliliters of water). Extraction is often expressed as a percentage (20% extraction is a good example) measured using a special tool – this is the process by which water pulls soluble materials out of coffee particles through contact.

Let’s not get lost in the numbers, though we’ll explore them more in-depth in a future post. This is about how to taste problems and what needs to be done to correct them. Let’s dig into what different concentrations can taste like, what different extractions taste like, and how you can fix each one.

“…the best way to wrap your head around this is to taste…”

Concentration

If a coffee tastes weak, watery, or tea-like (and not in a good way), it probably has a low concentration. This is likely due to a wide ratio (1:22, for example). This is generally the most un-inspiring brew. The solution is simple: narrow the ratio of coffee to water. Do this either by adding coffee or by using less brew water. The down side is that you can’t fix this after the fact – it’ll take a whole new brew.

If coffee has a high concentration it’s likely due to a narrow ratio (perhaps 1:10) – just the opposite of above. This coffee will have intense, heavy, very strong flavors and a lack of flavor clarity. The solution is equally simple as with low concentration – use less coffee or more water. The nice thing about this problem is that you can typically salvage a high-concentration brew by adding water to the brewed coffee. This process is called “bypass” and has valid applications in batch brewing.

Extraction

Separate of concentration flavors are problems with extraction. We suggest reading up on the concept from our previous post.

An under-extracted coffee is likely missing a lot of what the dry grounds of coffee had to give. Water wasn’t able to dissolve enough delicious compounds, resulting in flavors that are sour, salty, and overly sharp/acidic. This is typically the result of an overly-coarse grind, which means that grinding finer will help next time.

Over-extracted coffee has the opposite problem: too much was taken from the coffee grounds resulting in bitter, dry, ashy flavors. This is often due to your grind being too fine which means that coarsening up the next batch will help.

This is all interesting in theory, but the best way to wrap your head around this is to taste each of the four examples above.

Here’s a simple test you can conduct at home:

You’ll brew five small batches (pour-overs work well, but the fundamentals translate to all methods) of coffee:
Cup 1: Low Concentration – 1:25 brew ratio
This might look like 12g of coffee and 300ml of water using grind setting 15 on a Virtuoso.
Cup 2: High Concentration – 1:10 brew ratio
In keeping with the above recipe, this would be 30g coffee and 300ml water at the same grind setting.
Cup 3: Low Extraction – Coarse grind
This cup will have a standard 1:17 ratio, but you’ll grind at setting 30 on the Virtuoso.
Cup 4: High Extraction – Fine Grind
Still 1:17, this coffee would be ground at the lowest working setting.
Cup 5: Just Right
With a 1:17 ratio and a solid grind of 15 on the Virtuoso, this coffee ought to be just right.

Taste 1-4 and notice the flavors discussed above. Be advised, this is a gross experiment, but it’s extremely helpful in identifying the flavors you want to avoid. Finish off the test with that delicious Cup 5 to reward yourself for sticking through the test!

Going forward, you’ll be equipped with the memory of what these common brew issues taste like, so that you can identify them in less extreme cases. Using that mental toolkit, you won’t have to wonder what went wrong with your brew in the future – you’ll know just what to change.