What we think of as coffee is a roasted seed that has a wonderfully complex set of natural compounds and components. Those ingredients give coffee its distinctive aromas, flavors, body, acidity, and “feel”. Brewing coffee is simply using water as a solvent to extract components from ground coffee beans. The art of coffee brewing optimizes the extraction of desirable elements from the coffee and minimizes the extraction of less desirable compounds or byproducts of chemical reactions during the brewing process.
Before we get into specific remedies and issues, let’s cover some preventative measures you can take to improve the quality of your home brew. Coffee is not static. Its characteristics and quality will change over time and the rate and nature of the change are affected by many factors. Just like the brewing factors we have discussed in the first 4 parts of this series, timing and storage factors also affect the taste and quality cycle of roasted coffee. Here are a few things you can do to manage the readiness and life cycle of your coffee.
Resting and Proper Storage - Freshly roasted coffee needs some time to “rest” before grinding and brewing. One of the reasons is so that excess CO2 formed during roasting can be out-gassed. We recommend a rest period of 4-7 days from the date of roasting (4-5 for light-medium and up to 7 days for dark roasts). You should store your coffee in an airtight container at room temperature (never refrigerated or frozen) to minimize oxidation and loss of aromatic elements. We also recommend that when you reclose the bag, that you squeeze the air out through the valve to remove as much air as practical. If the coffee bag does not have a valve then try to remove as much air as possible before resealing. You might also want to reconsider your source if there is no valve.
The Shelf-life of coffee is indefinite but the life of a full flavor profile and freshness is not. The profile for roasted coffee starts to peak at around 1 week after roasting and is excellent for the next 3-4 weeks. It then starts to taper off. The coffee will still be drinkable even after a few months but will lose the more subtle and interesting notes in the profile. We recommend selecting coffees that have a clear “Roasted On” date rather than a “Best Before” date. Best before dates do not tell you how long it has been since roasting.
Freshly brewed coffee - You should drink brewed coffee almost immediately following the completion of the brew cycle. Over time, brewed coffee will lose many of its aromatic characteristics and, if it is kept heated or is reheated, the chemistry can change to the point that bitter and sour notes become more prominent in the profile. Having said that, I also recommend you taste your coffee over a period of time because different flavors will become more prominent as time goes on and the temperature drops. I don’t recommend reheating your coffee in the microwave the next day though unless you a desperate for a caffeine fix and are out of coffee and water. I wouldn’t bother taking notes on that one.
Troubleshooting Your Brew
If you have selected a great coffee, rested and stored your coffee well, and ground your coffee precisely just before brewing and it still does not come out the way you hoped then it is probably an issue with extraction or water chemistry. Assuming that you are using good, freshly roasted, specialty coffee and purified water (not distilled water or tap water), then there are some things that you can adjust to improve your brew. In this final part of the series we provide some common issues and ways to address them.
Common Coffee Brewing Issues
Weak and Underwhelming Coffee
Some people new to specialty coffee may under-brew the coffee. The brewing methods that make typical mass-produced coffee drinkable do not necessarily work well to produce a good cup of specialty coffee. This is almost always caused by under-extraction during the brewing process.
Adjusting for weak coffee: All that is probably needed are a few adjustments to your brewing technique to increase the extraction. Increasing the “dose” (coffee to water ratio), raising the temperature in 5 degree increments (but not over 205), increasing the time by a small increment, or reducing the grind size a bit will all increase extraction and the “strength and boldness” of your brew. Just don’t tweak more than one factor at a time and don’t overdo it. Small changes can make a big difference. You will know you are over-extracting when you start detecting bitterness or unattractive flavors and aromas in the brew.
Body and feel: If the coffee tastes ok but does not have the creamy or full body and feel you expected, try using a metal mesh filter rather than a paper filter. This will allow more of the natural oils to make it into the cup. If you want to “brighten” or “lighten” the body and feel, use chemical-free paper filters and rinse them before the brewing cycle. Use more than one filter to increase the brightness and lightness even more. Note that slightly darker roast levels will have converted more of the carbohydrates to sugars and these sugars will present as a bit more weight in the body and feel. That is one reason why lighter roasts tend to be "brighter" and darker roasts tend toward a heavier body.
Floral and subtle fruity notes missing: if you are missing some of the more subtle flavor notes present in the coffee you selected, such as floral and the less intense fruit notes, try extending the brewing cycle by small increments of time. They are probably there but not extracted in the concentrations that let them come through the more intense acid related notes that are extracted earlier in the cycle. Extending the cycle may balance the flavor profile in the direction of the more complex aromatic compounds that produce those notes.
As a side note, the techniques for preserving the shelf-life and adjusting body and the more subtle flavor notes will not usually work with mass-produced coffee. That coffee is generally over-blended, over-roasted and stale when you get it, so the notes and characteristics are missing from the coffee itself. That includes some famous brand coffees that are sold at retail.
Bad Tasting Coffee
When you start with good coffee, most issues that make coffee taste bad are caused by over-extraction, using unpurified water, some paper filters with residual chemicals and odors, or over-heating.
Sour: Sourness is usually caused by too much of the wrong kind of acid compared to other flavors. As we discovered in Part 2 of this series, coffee contains some acids that are sour and most of the time the culprit is Carbonic acid that is formed during brewing with the reaction of CO2 and water. The darker the roast, the higher the level of CO2.
The sourness caused by acids can be minimized by:
- “Blooming” – At the start of the brew cycle, wet the grounds with hot water and allow them to set for at least 1 minute. You will notice a layer of small bubbles (a bloom) forming on the surface and even larger bubbles coming up through the grounds. This “out-gassing” of CO2 will help reduce the carbonic acid levels in the brewed coffee. You can even do this with an automatic drip coffee maker. Just turn on the coffee maker until it starts delivering hot water to the grinds, and then turn it off and open the lid for a couple of minutes before turning it back on. This will not necessarily provide an even blooming but it will help.
- Extend the brew cycle – remember that acids are extracted first and then balanced by other flavors that are extracted over time. Add small increments of time to the brew cycle but, be careful not to extend the brew cycle too long and introduce undesirable notes like bitterness. If it is on the edge, try lowering the temperature 5 degrees on the extended cycle length.
Bitter: If the water is in contact with the coffee too long or at a temperature that is too high, some compounds that are less desirable may be extracted in higher amounts causing bitterness. Finer grind levels will also increase the extraction rate and may contribute to bitterness if other adjustments are not made.
If your coffee is bitter, try lowering the temperature, decreasing the brew time, or increasing the grind size to lower the extraction. Also make sure you rinse the paper filters you are using to remove any residual chemicals used in the manufacturing process and anything picked up from the air in storage. Paper filters are a magnet for airborne smells. Store them in an airtight container, especially around the kitchen. If you used tap water then switch to purified water. The chemicals used to treat public water supplies react poorly with coffee in even tiny trace amounts.
Burned: If the coffee tastes “burned”, a smoky bitterness, there are several likely reasons. But before you decide that it is “burnt” try a few more sips over a period of a minute or so. There are some naturally occurring compounds in your mouth that react with certain compounds in coffee that may give you that burnt taste or sensation on the initial sips.
If it still tastes burned after the initial sips then it usually because the coffee is “over-roasted”, it is stale (over oxidized), or it was over-heated. If the coffee itself is ok, then try lowering the temperature.
If the bitterness crept in by keeping the coffee heated for extended periods or reheating it after the brew cycle then you know why we recommend drinking the coffee freshly brewed. Coffee is dynamic and there is a lot of chemistry going on over time. Some of the changes can unbalance the profile and result in undesirable flavors and sensations. Never reheat coffee or use a “percolator” that reheats brewed coffee and sends them back through the grounds.
Experiment and Explore to Optimize Your Brew
To brew your coffee just the way you like it will take some knowledge, tools, and practice to master, but you can focus on one or two techniques and enjoy the journey as you learn. Start with what you already know, the instructions for your brewer, grinder, and coffee and then learn to diagnose issues and adjust your brewing to dial in on that perfect brew. Here are a few things that can help you make continuous improvements and optimize toward your perfect cup of amazing coffee.
Be consistent. Use your scale, thermometer, and timer. Keep notes on time, temperature, and weights used for each coffee batch. Note the results and use those measures consistently on every batch. Small changes can make a big difference.
- Do small tasting batches. While you are optimizing your brewing technique, or adjusting for a new coffee, do multiple small batches. Also note how the flavor profile changes over time and temperature as it cools for every batch. This will provide clues on the full flavor profile and what you can do to optimize it when you are brewing larger batches.
Learn to “diagnose” specific taste issues. Learn to recognize individual issues and isolate them from the overall taste. Focus on one issue at a time. This doesn’t require special skills, or genetics, you just need to pay attention and learn to detect different tastes and sensations in each batch. Focus on different parts of the aroma, your tongue, and mouth. Think about what the tastes and sensations remind you of. What do you like and what do you not like about them?
Change one thing at a time. If you want to make adjustments, change one variable at a time for each batch. You won’t be able to determine the effect of specific adjustments if you change too many things at once. Most of the time that will be either time, temperature, grind size, dose or filtering – but just one of them at a time.
- Experiment and discover. Good coffee is complex and balanced. There are many different flavors and sensations but none of them are so overwhelming that they bury the more subtle flavors and delicate sensations. Since these flavors and sensations are produced by various compounds in coffee that have different extraction rates and chemistry, making small adjustments can optimize for the balance and profile you prefer. Even the filter you chose can make a difference. Try different combinations and explore the reaches and depth of your coffee.
Try Blending - Some purists will hate me for this but I like exploring different flavor profiles. One morning we had a small amount of coffee beans left over from two different micro-lot specialty coffees. One was bright, floral, and berry with a creamy body. The other one was more citrus and dark chocolate. As an experiment (and being too lazy to make two small batches), I mixed the beans together in the grinder and did a pour-over of the mix. It was really good. I now do that more often. I typically use a ratio of 2/3 of lighter, fruitier coffee and 1/3 of a more chocolatey, nutty one. I also try this approach with the same coffee that is roasted in two batches at different levels. I use a higher ratio of the Medium-Light roast and a smaller amount of the darker roast. Everyone’s tastes are different and there are no rules. So just have some fun and adventure experimenting with the amounts and blends and see what you can come up. Just make sure you take notes in case you want to try that again.
In this final installment of the series we have covered some of the basic troubleshooting techniques to improve your coffee brewing. We have also provided some suggestions on experimenting and optimizing your coffee selection and brewing in your quest for an amazing cup of home brewed coffee.
We hope this series has been informative and helpful. While we can’t provide a single perfect recipe that applies to every taste, coffee, and brewing method, our intention was to provide you with the knowledge to explore and discover your own perfect recipe. Everyone’s tastes are different and there are no rules. So just have some fun and adventure experimenting with the amounts and blends and see what happens. Just make sure you take notes in case you brew that perfect cup and want to it again. Have some fun and happy brewing!
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