Better Your Brew Series || Volume II Ch. 2 of 3 || When Good Coffee Goes Bad: Troubleshooting Your Brew

Alright, we discussed every variable and how to manipulate them to target your favorite cup. Now, we talk about what to do when something is still not working out. Below are many issues I could think of that I have experienced myself or seem common. Keep in mind that I make suggestions for each on how to troubleshot, but the order of my recommendations is not necessarily the correct way, and my suggestions are not exhaustive. Finally, remember that if you change one variable it can impact others, so you need to keep that in mind. For example, if your drawdown is too slow so you grind more coarsely, you will decrease extraction and get a weaker cup. To compensate, you may need to increase water temp or increase your dose.

WHEN GOOD COFFEE GOES BAD || Chapter 2. Troubleshooting Your Brew

Coffee tastes sour

Likely it is under-extracted. You can try to fix this by increasing your contact time, your brew time, by grinding finer, using a hybrid for immersion pour, using a slower brewer, or increasing your water temp. I would start by grinding finer as long as your coffee is not taking too long to drawdown (usually no more than 3-4 minutes total depending on your brewer). If it is still finer or you cannot grind finer with your brewer and filter, I would increase water temp. It sounds counter-intuitive, but if it is still sour then I would grind coarser and see what happens. Especially if your drawdown time is more than 4 minutes. Sometimes if you grind too fine the water will channel and you can get sour in your cup. If it is still sour, you may want to try different beans. Lean more towards a Colombian washed and steer away from anything from Ethiopia, especially labeled as Guji or Shantawene, and avoid processed coffee labeled as anaerobic or carbonic maceration.

Coffee tastes bitter

Likely over-extracted. The first thing I would try is to grind coarser, especially if your drawdown time on the longer end, around 3:30 minutes or more. A long drawdown time is not necessarily a bad thing, but if your brew is bitter then I would start there. If that doesn’t work then I would lower your water temp and I would pour gently with little to no agitation. This will help avoid extracting those undesirable compounds. If it is still bitter, then it could be your roast. If it is a dark roast it is going to be easier to get bitter flavors. I would try a roast that is more medium and see if anything changes. Your water chemistry can also always be a culprit, but this would tend to cause more muted flavors or possibly highlight acidity too much. That said, sometimes people confuse bitter and sour. You can learn the difference by comparing how lemon juice tastes in comparison to something like vinegar or bitters.

Coffee tastes weak or watery

Most likely your dose is too low and you used too much water over your coffee. If your coffee tastes okay except the flavors seem weak and the body seems too light, like tea, then I would try your next brew with a 1:14-1:15 ratio. If that solves the problem but you then feel the coffee is too strong, you can always add 20g of water as bypass and taste, continuing to add until you get the flavor and body you want. If dropping your ratio doesn’t work, then you may need to grind finer. If your drawdown is quick, for example 1:30 in a V60, then you need to give the coffee more time to interact with the water. Usually this means the coffee would also be sour, but it is not guaranteed. Also, if you have a very light roast, what some people call a “Nordic roast”, then you may be brewing correctly but just not a fan of the tea like body and more nuanced flavors. Sometimes Gesha varieties can present this way for some, with tea-like body and soft, floral notes. Try a punchier coffee, maybe something that was processed as anaerobic or at least a natural. You can also try a different method, like a french press or AeroPress, to get a bigger body.

Coffee tastes too strong

If the coffee is not taking too long to draw down and does not seem overly bitter or dry, then you likely just need to expand your ratio. If you are brewing a 1:15 then try to go up to 1:16 or 1:16.5. Also, before you throw out your overly strong cup, if it is not bitter or dry then simply add about 20-30g of water to the coffee to see if this helps open it up more and balance it out. If not, try to add another 10-20g. This should help you identify if it is your dose/ratio. If not, then you may need to try a lighter roast of coffee or a mellower bean. Sometimes coffee from Sumatra or India can seem too “strong” or overwhelming. Try a washed coffee that is a lighter roast, and use a 1:16 - 1:18 ratio.

Coffee tastes flat or dull

This could be a number of things. Your coffee may be too far off roast, or stale. Look at the suggested rest times discussed earlier in this book and see if you are still relatively close to the suggested rest times. If the coffee is too fresh or too far off roast it can result in a flat or dull flavor profile. Also, the roast could be bad. Sometimes you may get coffee from someone who may not be consistent as a roaster, or it was just a bad batch. Also, if it is a super light roast then it has to be roasted quite well or you can get flat flavors or even grassy or vegetal flavors. The first thing I would check is how fresh your beans are, after that I would consider your water chemistry. Tap water can easily mute flavors in coffee due to the bicarbonates. If you have a coffee you know should taste good, try to get some distilled water and mix in about 1/3^rd-1/2th tap to keep a lower TDS, around 75ppm. The more precise way would to be using Third Wave Water to make water with precise mineral measurements, or add Lotus Drops to your cup to try and highlight the flavors you are looking for. Likely the beans are too fresh or stale, and/or your water is muting the flavors.

Coffee is overly acidic

This may be due to under-extraction and confusion between acidic and sour. If you feel you are brewing well, your drawdown time is around 3 minutes in a V60 and no stalling the brewer, then it could be your water. If you have too much magnesium it can cause your coffee to be overly acidic. It could also be due to the variety and origin of the coffee and the roast level. Ethiopian coffee tends to be more acidic than coffee from Brazil, for example. If you are using a conical brewer, try to use a flat bottom brewer to balance the acidity out with more sweetness. Better yet, try a hybrid brewer like the Pulsar or Hario Switch to add in some immersion time to balance out the acidity. If all you have is a V60, you can also throw a Kalita Wave flat bottom filter in and that may help, or grind finer until you hit bitter and back off a little. Otherwise, it may be a poorly roasted coffee.

Coffee is astringent or dry

This often occurs due to channeling or over-extraction. If the water is in contact with the coffee too long it begins to pull out compounds that do not really add anything to the final cup. The first thing I would do is coarsen your grind slightly and drop your water temperature slightly. If that doesn’t work, I would reduce the number of pours, so if I am using 4 pours I would drop to three. I may even add cool water in the kettle and drop the water 10 degrees Celsius for the last pour. The cooler water will not be as effective at pulling the astringent or bitter compounds that are left in the coffee. Lastly, I may remove my last pour or cut it in half and add the last of my water as bypass.

Coffee tastes too earthy or muddy

This can be common for some coffee origins, like Sumatra or India. This has to do with the coffee being grown in low altitudes as well as the typical process of that area. India may use the monsoon process, and this coupled with low region origin can lead to an earthy taste. The roast can also contribute to this, if the coffee is roasted too light it allows some of the grassy or vegetal flavors to remain. If this is the cause, you can try coffee grown at a higher elevation and using a different process, such as washed, or try a more medium roast. Grinding too fine can also cause a muddy bed in the brewer and cause fines to clog the filter. A muddy bed is not necessarily the sign of a bad cup of coffee, but it can be a symptom of poor grind or pour technique.

Coffee has no sweetness

This can be due to the coffee, the roast level, the water, or the way you are brewing. The first thing I would try is to increase the time your water is in contact with your coffee after your initial bloom. If you are using multiple pours, try to reduce your recipe to three or even two pours. For example, if you have a 20g dose and you are using 300g of water for a 1:15 ratio, try blooming for 45 seconds with an initial pour of 60g. Then break your remaining water into two more equal pours of 120g each. Or, pour the remaining water as one pour after your bloom if the brewer allows it. If you are able to use a low to no-bypass brewer that will also help. Higher-bypass will tend to increase acidity and clarity, which can over-power the sweetness. Essentially if you want a sweeter coffee you want to use less pours and have less bypass, in general.

You can also use a hybrid brewer if you want to have an immersion pour. You could use the Next Level Pulsar or Hario Switch and close the valve on one of your pours for a few seconds to allow more time to pull out any sweet compounds. Be aware that this will increase body and it can also increase bitterness depending on when you use the immersion pour or for how long. If you are using a conical brewer, I would switch to a flat bed brewer. Conical brewers tend to highlight acidity or fruitiness rather than sweetness. If the coffee is still not sweet enough, you may want to look into a different coffee or maybe a more medium roast if you are using light or dark beans. Your water could also be muting sweetness if the minerals are not balanced correctly, so adjusting your water may help. Lastly, you want to taste the coffee around body temperature, because this is when we are able to best perceive sweetness.

Coffee is too sweet

I have never personally experienced this issue, but I am sure it has happened to someone. For me, it would be more about sweetness in relation to other flavors, like sweetness being too high and overpowering the other flavors I like. For this, I would first try to change the brewer or the grind size I am using. If I am using a flat-bottom brewer, I may switch over to a conical, like the Origami, V60, or UFO dripper. This would focus the extraction on pulling out the original acidity in the beginning and balancing out with sweetness. If this overcompensates, I may then grind a bit finer to allow more contact time to balance out the later compounds, or decrease the number of pours I use, with a larger pour for a 2^nd or 3^rd final pour after the bloom.

An example may be 20g:300g at 1:15 ratio. 1^st pour 75g bloom for 45 seconds. Then pour 100g and wait for drawdown, then final pour with remaining 125g. Or I may bloom with 75g and then pour the remaining water of 225g in one more pour. This will focus more on extracting some of the sweetness and not so much of the acidity right out the gate. You also do not necessarily need to switch brewers. You could just change your pour structure or change your grind and try to balance the cup more. The next culprit could be your water, as usual. And lastly, it may just be the origin, varietal, and/or processing type of the bean you are using. Especially if you are using a co-ferment coffee (coffee that is fermented with actual fruits added to it).

Coffee tastes “burnt” or over-roasted

Your coffee may be burnt… This is not just dark roasts either, during the roasting process one of the defects that can occur due to roasting is burnt beans, as in a burnt flavor and not necessarily burnt surface. There are a handful of defects that can occur during roasting, tipping, scorching, baking, etc. If you are brewing a dark roast, then it is not uncommon to get smoky or burnt flavors, as dark roasts tend to be more suited for espresso and milk drinks rather than pour over.

Other than trying a lighter or different roast, you could also try to reduce the likelihood that you are extracting too many bitter and astringent compounds. These, mixed with a nuttier coffee, could easily come across as a “burnt” flavor. The first step here would be to reduce the temperature of your brew water. If you are using a dark roast, you should try below 85 Celsius, or lower, and see if that helps. This will help to reduce the more bitter compounds getting into the cup. You can also use less water to brew your coffee, which may be pulling out astringency. If you continue to pour water of coffee grounds that are already extracted, you will just get watery dryness. You also want to make sure your coffee is adequately rested, or you will get a bitter or chemical flavor due to the heavy CO2 present.

Inconsistent flavor between cups

If you are getting noticeably inconsistent flavors between cups using the same bean, then there is a variable that is not the same. If you do not have a decent grinder then you may be getting very different particle distribution each time. If you are not using the same water this can happen. If you are brewing at different times of the day, then this could occur due to changes in humidity and weather. If you are changing how you agitate the coffee, perhaps sometimes swirling, sometimes stirring, sometimes not anything, then this can change your brew. Something is not the same somewhere, so I suggest you go through your routine to make sure you are not changing anything. This is also why you need to use a scale, dosing, and other precise measurements cup to cup. The final culprit is time. As coffee ages it will not only change in flavor, but you will need to adjust variables to dial it in again. A coffee you dialed in a week ago may taste different unless you grind slightly finer, or use 2 degrees hotter water, etc.

Tastes nothing like the bag says

The tasting notes on the bag were a subjective experience by someone that was brewing the coffee in a completely different way than you, with different equipment, in a different environment, and with the coffee off roast at a different time. Even the water they were using was different, which can make a huge difference. Flavor notes are mentioned as a general suggestion of what may be found in the coffee, and to get closer to precise flavor notes you would need to brew the coffee exactly as the taster/roaster intended it. Sometimes roasters will provide recipes with their coffee, but not always. Beans are scored and flavors are identified through cupping, which is a specific type of immersion brewing that differs greatly from pour over. If you are not getting the same notes as the bag says, that does not necessarily mean you are doing anything wrong. If the coffee tastes good to you, that is all that matters.

Coffee drains too quickly

First thing I would do is grind finer. If this works but results in the coffee tasting bitter, then I would try grinding slightly less fine and decrease my water temp to lower extraction. Next, I would consider using a different filter. Perhaps I am using a faster flow filter like Sibarist, I could try to switch to a traditional Hario filter or a Cafec T90.

Coffee brews too slowly or stalls

First thing I would do is coarsen my grind. If you grind too fine this can clog your filter and create too much resistance for the water flowing through. Next, I would consider using a different filter. Perhaps I am using a Cafec T90 filter, I could switch to Origami or Sibarist filter and speed up my drawdown time. Lastly, I would consider my brewer. Some brewers are inherently faster or slower and are meant for specific grinds and types of coffee. I may need a faster flowing brewer for the coffee I am trying to extract.

Channeling (water flows unevenly through the bed)

The first thing I would look at is my grind size and consistency. If the coffee is too coarse the water will flow quickly through large pathways, if it is too fine the water may push through and make channels through weaker parts of the bed. If the particle size is very inconsistent then some areas will pack together more tightly than others, and the water will find the path of least resistance. You also want to consider your pour technique. Make sure you are evenly distributing water across the bed and not favoring one part of the bed. If you pour your water mostly on the left side of the bed it will dig a channel through this area at a faster rate than other areas. Also, consider your filter. If you have a poor quality filter and/or the filter is clogging from fines, then water may struggle to pass through evenly. Finally, this could be due to a poor grinder. You can either sift the coffee to get a more even particle size, or use an immersion or hybrid brewer to mitigate the poor grind.

Grounds stick to filter sides

If you have a few grounds that stick to the filter at the end of the brew this is not necessarily a concern. It can give you some insight into how many fines your grinder is producing, though. To avoid this you can gently swirl after each pour to wash any grinds down and even out the bed. You can also lessen your agitation when brewing. So do not stir the slurry and try to pour with a slower rate and pour closer to the coffee bed. Agitation tends to spread fines and they can stick to the filter and also settle to the bottom and clog your filter. Lastly, make sure you pre-rinse your filter, as this can help with this issue as well.

Bloom is weak or non-existent

If you are not seeing a noticeable bloom (coffee grounds expanding and/or bubbles releasing from the top of the slurry), then the first thing I would look at is the freshness of my beans. If the beans are quite far off roast or maybe they were not kept in a well-sealed container, they may be staling. Next, consider your water temperature. CO2 is not generally difficult to extract and does not require incredibly high temperatures, but if your beans are a little far from roast you may need to use a little bit of hotter water to pull out any remaining CO2. Lastly, just follow your recipe as normal and see how the coffee tastes. Sometimes I will brew a coffee I know is still fresh and not see much happening during the bloom, but it will taste just fine.

Water bypasses the coffee bed

If you notice you are getting too much bypass, then I would look at the brewer and the filter. If you like the resulting coffee but feels too much bypass made into the cup (by visual observation or a light body), then you can try a different brewer or filter. For example, I may switch from a high bypass brewer like the Origami to the Orea, which can be low or no bypass depending on if you use a flat filter or a wave filter. Next, I will look at how I am pouring. If I am pouring too much water in a single pour and the water level is rising high above the coffee bed, this can cause a lot of bypass if your brewer has ridges for the water to escape and navigate around the coffee bed below.

Water pools on top and won’t drain

This is due to a clogged filter or stalled brew. See above on how to manage a stalled brew. Essentially, grind coarser, use a faster flow filter, try a faster brewer. You may also have too many fines due to your grinder and too much agitation forcing them into the filter. Try to decrease agitation.

Filter collapses

Be gentle when wetting the filter. Many filters must first be folder or shaped before they are placed in the brewer. Then you want to try and keep the filter in place while you slowly start to wet the filter. The water will then help the filter to take shape and attach to the brewer. Do not pour too fast or the stream may collapse the filter. Some brewers also have tools they typically call a “negotiator” that you can use to help you shape the filter to the brewer.

Coffee bed isn’t level

Simply swirl the brewer after each pour, ensure your brewer is level, and ensure you are pouring evenly across the entire bed and at a steady flow rate and speed. You can swirl the bed gently rather than stirring to reduce agitation.

Dry pockets of grounds after brewing

This means you likely had channeling and you did not bloom well enough. First off, make sure you use plenty of water for the bloom to make sure all coffee grounds are saturated. A general rule of thumb is to use at least 2x water to weight of coffee ground. I personally prefer to use 3-4x to really make sure all the coffee is saturated and ready for extraction. You also want to look at your grind to make sure it is consistent and you do not have a lot of fines and boulders. Lastly, make sure you are pouring at a steady rate and moving across the entire bed of coffee to saturate all grounds evenly for every pour. Something to keep in mind is that a conical brewer means your coffee bed is much deeper in the center, so you may need to stop and pour just in the center for a moment before or after you spiral across the rest of the bed. Or star with a center pour before spiraling for the initial bloom pour. I will also use a stir stick to stir the bloom to ensure there are no dry pockets.

Slurry rises and overflows the brewer

Pour less water for each pour. If you need to, spread out the water across more pours so you do not have too high of a water level above the coffee. Your other options are to get a larger brewer, use a smaller dose, or brew a concentrate of 1:10 and add the other water as bypass to reach the ratio you like.

Splashing or sloshing during pour

Do not pour so fast or lower your kettle closer to the coffee bed. If the stream of water coming out of your gooseneck kettle is breaking before it hits the bed, you are pouring from too high.

Uneven saturation during bloom

Make sure the coffee bed is level before you start your bloom by shaking the brewer. You may need to add a divot in the middle of the bed for conical brewers so the water can get to the deeper part of the bed. Try using a larger amount of water for your bloom, like 3-4x the weight of the grounds in water (i.e. pour 60-80g of water over 20g of coffee). Pour a bit faster and more aggressively for the bloom pour. You can decrease agitation after this initial bloom and still have no issues with settling fines or clogging the brewer. You can also try hotter water, which will be able to travel faster through the coffee due to lower viscosity, but then you have to manage extraction levels in the final cup.

Sediment or grounds in final cup

This is something you cannot much avoid if you are using a metal filter. If using a paper filter, then you may need to try a different filter that is better quality or thicker. The other common issue is that you either are grinding too fine or your grinder is producing a lot of fines (tiny particles) that are making their way through the filter and into your cup. I would first make sure the filter did not tear, and that I am using a decent filter. I would then try to coarsen my grind to avoid so many fine particles. If the coffee tastes good, other than the fines, do not waste it, simply load a fresh filter, rinse the filter, and pour the coffee through. This will get more of the fines out of the coffee so you can salvage the cup. However, it is not a very sustainable way to brew.

Coffee tastes different when scaled up or down

This is because one variable may impact another. If you increase the dose then the water has to travel through a deeper coffee bed, and the dynamics of the brewer may also change. If you change your dose then you need to consider how this may impact your final cup. If you decrease your dose, say form 20g to 15g, you also need to decrease your water to maintain the same ratio if you want a similar flavor profile and body. I would suggest you decrease you water to match your original ratio, and I would grind slightly finer since the coffee bed will now provide less resistance to your water, decreasing contact time and extraction. If you increase your dose, you need to increase your water, and I would grind slightly coarser or use a faster flow brewer and/or filter.

Inconsistent grind size

This is going to be your grinder. You only have a couple of practical options here, and one expensive one. The expensive one, purchase a better grinder. Other than that, you can try a couple other methods that may improve your cup, but they also have a cost. You can grind your coffee again. Yes, use the same grinder and put the grounds through again. This will improve particle size distribution, but is not ideal and can be tough on some burr grinders. So this is a very short term, back to the wall option. The other option, sift your coffee. If you have a baking sift, pour your grounds in and separate out some of the fines or the boulders. The downside to this, you lose some of the complexity because having different particle sizes provides layers of flavor. However, this is truer when you use a decent grinder and your grinds tend to be mostly in two main ranges of particle sizes. If the grounds are all over the place, the cup will be a mess, not complex. Lastly, switch to immersion brewing, like a French Press, AeroPress, or close the switch on a hybrid brewer. This will mitigate some of the issues of poor particle distribution.

Wrong grind setting

This has definitely happened to me before, half asleep trying to grind my first cup of the day. In order to save your grounds, you have a couple of options. One is to use the grounds for a different brew style. So, if you grind to coarse you could use a French press, if you grind too fine you could use an AeroPress. If you are dead set on using these grounds for a pour-over, then you may need to change your brewer and your filter. If I ground too fine by accident when trying to use my slower flow Orea brewer, I may pull out my faster flowing Origami and even throw a super-fast flow filter in it, like a Sibarist. If you grind too coarse, you could use a higher temp water to increase extraction, and switch to a flat bottom brewer if you were trying to use a conical. This would help slow down the flow and the higher temp would help increase extraction with a shorter contact time.

Not sure how fine/coarse to grind

This can be a tough one, especially in the beginning. My best advice is to go online and do a little research the first time you try pour-over or a new coffee or brewer. It will not be perfect, but a lot of times the nicer grinders will have a chart on their website or online that suggests a grind setting for their specific grinding based on the type of brew you are wanting to do. Worst case scenario, take a guess, pour your recipe, and assess any issues by watching the brewing process and tasting the result. This is not uncommon even for long time enthusiasts if they get a new brewer or a new coffee they are not familiar with.

Coffee clogs the filter

Too many fines, you need a better grinder. The cheaper option, sift your coffee to remove the smaller fines. You can get a coffee sifting cup on Amazon or elsewhere for less than $20. The downside, you may possibly lose some complexity. But hey, a slightly complex coffee is better than no coffee. You also may need new filters, some have poor design. Lastly, make sure you are not agitating the coffee a lot when brewing. This may be less of an issue with a washed coffee, but if it is an anaerobic or fermented coffee then agitation will not be your friend.

Can’t control pour rate well

This comes with practice. If you do not have a gooseneck kettle, then you won’t really be able to get a consistent pour. I would suggest you purchase a gooseneck kettle and then practice to get better. You can place your free hand at the base or top of the kettle when pouring for more stability. You can also purchase a drip assist (like the Melodrip) until you get better at pouring. The drip assist will distribute the water at an appropriate flow rate and evenly across the bed in a consistent manner.

Water temp not accurate

Sounds like you need a better kettle or thermometer. Otherwise, the kettle may be correct, but you are losing a lot of heat before the water makes it onto the coffee. You can lose heat from leaving the kettle off the heat too long, pouring into a cold brewer you did not pre-heat, pouring though a cold gooseneck spout, or during the time it takes the water to pass from the kettle spout onto the bed as it passes through an air-conditioned room.

Scale not responsive

You probably just need a new or better scale. I don’t really know of any other option for this one. Sometimes scales are just slow or unresponsive. udo want a scale that can measure to a tenth of a gram at least. A 14.2g dose is different than a 14.8g dose, but you will only see 14g for both if you do not have a scale that measures to a tenth.

Filter doesn’t fit brewer properly

You may have the wrong filter. For example, you may have Origami papers that fit your V60 perfect, but then you go to use the UFO Dripper and find the filters are too narrow. Different brewers are different sizes and have different angles to their shape. Some filters are interchangeable, but not all are. You could invest in round, flat filters that you can shape pretty much to any brewer. Some brewers even come with a negotiator that helps to push and shape the filter to the brewer. Some filters will also fit with a bit of folding. I use Origami papers for the V60, and I have to fold the top in more than the bottom, so they fit correctly.

Grinder retention or static issues

This can be an issue with lower end grinders or commercial grinders. Commercial grinders will typically use hoppers and they retain many grams of grounds in the burrs and chamber. At home, some electric grinders are better than others at minimizing retention. Hand grinders will produce the least retention. If I put 15.5 grams of coffee into my 1Zpresso ZP6 Special hand grinder, I get 15.45-15.5 grams out. If you have an electric grinder at home that has high retention, first is to consider how old your burrs are. Next, other than buy a better grinder, you can try to use a knocker if the machine has one, to knock grounds loose. You can get an inexpensive handheld blower, or even purchase a can of compressed air to blow the grinder out after every use. For static, I use a dryer sheet to wiped own the chute of my DF54 electric grinder and this helps decrease grounds sticking to the chute for a few uses. I also use a stiff bristle brush to clean the chute after every use. These methods will help, but some will only help clean the grounds out not address the fact that you put in 20g and got 19g out. In that case, figure out the typical retention of your machine, and add that much extra to your beans going in.

I am sure there are many other issues you could run into, but this is as exhaustive as I could think of. Feel free to comment below with any other issues you may have run into or with any comments or questions. See you in the next post, where we discuss coffee myths, misconceptions, and controversies.