One of our favorite ways to make a cup of coffee is with a pour over- essentially doing the work of a drip coffee maker but yielding far better tasting results. A pour over setup generally consists of a vessel, like a mug, a gooseneck kettle, a pour over cone, and a cone shaped coffee filter - for a re-cap of pour over basics generally, see our Pour Over Guide.
With all of the variables that contribute to the final product, such as grind size, pouring method, and so on, a number of things can go wrong to cause your coffee to be less than ideal. In this, we will go over the steps necessary to troubleshoot and then correct some common problems leading to pour over under extraction.
What is "under extracted coffee"?
How do you know if your coffee is under extracted? One easy way to potentially identify under extraction is by the color and overall appearance of your brewed coffee: under extracted pour over coffee will be significantly lighter than its properly brewed counterpart, as well as have a duller and an overly transparent appearance. Correctly brewed coffee has a shine to it from the naturally occurring oils in the grounds and should be mostly opaque.
While appearances vary slightly depending on the roast and type of coffee being used, the main indicator of under extracted coffee is the taste. Think about free coffee you've received at a hotel or cheap gas station- usually it looks and tastes a bit "thin". If your coffee has that type of flat, thin, sour taste, your coffee is probably under extracted.
Troubleshooting Under Extraction
We are initially going to look at the two biggest considerations for ensuring proper extraction. Then, we'll cover three other things you should double-check if you are having problems with under extraction.
Tip #1: Finding the Right Grind
The first step to diagnosing under extracted coffee is to look at the grind. Generally, pour overs use the same fineness that drip brewers use- the “paper filter” setting on a grinder.
If you notice that the water passes from the gooseneck kettle through the grounds and filter exceptionally quick, the first thing to adjust is the grind to make it slightly finer. A bitter flavor normally indicates over extracted coffee - try grinding coarser. A sour flavor normally indicates under extracted coffee - try grinding finer.
Next, you should consider your pouring technique.
Tip #2: Getting the Proper Pour
Letting your Grounds Bloom
When pouring, you want to let the coffee grounds bloom before continuing on and pouring the remaining water, as brewing the whole cup with one pour can easily lead to under extraction. To bloom the grounds, simply pour about 50 grams of water over the grounds with the purpose of covering as many of the grounds as possible with as little water as possible. You’ll notice the bed of grounds rising up as the gasses escape. After about 30 seconds, continue the pour. Allowing the grounds to bloom first and letting the gasses escape prepares the grounds for brewing.
Having the correct pouring technique is another important consideration for avoiding under extraction. For proper pouring, start a two minute timer right when you bloom the coffee. After blooming, you’ll be aiming for two to three additional pours. Doing multiple pours, instead of just one or two total, allows for the grounds to settle back down and for the water to linger around longer. Pouring all of the water at once causes it to be pushed through the grounds too quickly, as there is additional and unnecessary downwards pressure from the excess water.
While pouring, aim for both the dark spots and the grounds that crawl up the inner sides of the filter, but try to maintain a circular spiral motion with the tip of the gooseneck kettle. Pouring from too high will overly agitate the grounds, so try to stay closer to the bed of coffee rather than further, but slight agitation is actually preferable. The duration of each pour really comes down to how many you’ll end up doing, but all 400 grams of water should be passed through at around the two minute mark.
If your pouring technique is top-notch, then continuing to adjust the fineness of your grind is the best way to go. You can dial in your grind by continuing to brew and sample, gradually making your grind finer and finer until you reach an optimal level of extraction.
Tip #3: Correct Coffee-to-Water Ratio
You should also ensure that you are using the right coffee to water ratio. Under extraction will occur if not enough coffee is being used, or there is more water than necessary being poured through the pour over. A good ratio is 25 grams of ground coffee to 400 grams of water.
Tip #4: Evenly Distribute and Tamp Your Grounds
You should ensure that your grounds are tamped down and evenly distributed inside your filter. Grounds that are poorly distributed or too loose won't force the water to extract sufficiently out of them.
Tip #5: Correct Water Temperature
Lastly, if your water is not hot enough it will fail to extract the necessary oils from your grounds, leaving you with an under extracted cup. Make sure you aren’t letting your water cool too much after reaching a boil.
Are you sure my coffee isn’t over extracted?
Maybe you’ve figured out something isn’t right with the flavor, but aren’t exactly sure what. How do you know your coffee isn’t over extracted instead of under extracted? In contrast to the sour, thin taste of under extracted coffee, over extracted coffee will taste overly bitter and even astringent or dry like a wine. If these adjectives match the flavor better, you may want to consider whether your coffee is over extracted. Troubleshooting over extraction basically involves the steps discussed above, but in reverse (increasing grind size, reducing the amount of coffee per water, etc.)
With all of this in mind, the key to brewing perfect pour over is patience and the willingness to really dial in the technique. Don’t feel bad if it takes a little while to figure out the right proportions and technique, because learning is just part of the journey.