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Writer's pictureSam Choi

6 Mistakes Made by Cafes that Affect the Quality of Coffee

Updated: Nov 5, 2021


6 common mistake made by cafe

I believe many of us dream about our own cafe with beautiful concepts and good quality coffee. But do you think opening a cafe is easy? Do you know that if we do not have knowledge and care, our coffee will turn bad fast? If you love Premium Coffee or even Specialty Coffee, you need to know 6 common mistakes made by the cafes that affect the quality of coffee.


Please follow us to understand what those 6 common mistakes are. Only you know quality, you can brew quality and serve quality.


Mistake 1 - Incorrect Storage of Roasted Coffee


Roasted coffee is notorious for having a very short shelf life. Even through large brands mark their best before date as 1 or even 2 years; you, I, and everyone else in Specialty Coffee knows that roasted coffee loses its prime very fast. A good general practice is to use roasted coffee in your cafe within 1 month of the roasted date. But the shelf life of your roasted coffee must be evaluated along with its storage condition. The best storage condition for roasted coffee is cool, dry, and dark. It is also critical to limit the amount of contact between your roasted coffee and oxygen (air) to reduce oxidization which causes the rancid taste in stale coffee.


Usually, you will receive your roasted coffee in sealed bags. Keep your roasted coffee in their sealed bags and keep them somewhere cool, dry, and dark until you are ready to use them. When needed, put only the amount of roasted coffee you use within 1 work shift into the grinder. The grinder is usually placed right next to the espresso machine and is exposed to heat, moisture, light, and oxygen; which is really bad news for your roasted coffee. Seal the remaining roasted coffee in its bag or another airtight container after removing as much air as possible. If your cafe does not consume a lot of roasted coffee, it would be advisable to request your roaster to pack your roasted coffee in smaller amounts.


In order to maintain a flow of fresh, well-rested roasted coffee from your roaster, it is critical that you keep a record of your roasted coffee use and plan your orders to meet your customers' demands. Ordering too much will mean that as you get to the end of your batch your roasted coffee would have lost its flavour and maybe even developed some rancid taste. Ordering too little will mean that you will need to use roasted coffee that hasn't had time to rest thereby not reaching its prime, or worse you will not have any coffee to serve to your customers.


It can be challenging as a Specialty Coffee enthusiast and business owner to serve the best quality cup of coffee to each one of your customers, but with knowledge and care, the quality of your coffee at your cafe does not need to suffer.


Mistake 2 - No Daily Equipment Maintenance


As the saying goes, "Prevention is better than cure". The best way to keep your cafe serving high-quality cups of coffee is to invest time and effort into daily maintenance. Weekly, monthly, semi-annual, annual maintenance are important, but it will be things that you do on a daily basis that will produce consistently high-quality espresso drinks flowing. (For weekly, monthly, semi-annual, and annual maintenance, check your machine manufacturer's recommendations.) In the café, you have two machines that have the biggest impact on the quality of your coffee - your grinder and your espresso machine. There are important steps you can implement in your café to ensure that you will get the best quality on every shot.


For the grinder, if you have not used the grinder within an hour, purge the grinder of around 5g to remove any stale ground coffee that sits between the burrs, in the grinding chamber, and the chute. This will avoid any stale coffee going into your portafilter. On the other hand, if your café is busy, keep an eye on the temperature of the grinds coming out of your grinder. As your burrs work hard, the temperature will increase in your grinder. Usually, as your grinder heats up, you will need to grinder a bit finer in order to achieve the same extraction time.


At the end of the day, make sure to empty out your hopper and store your beans in an airtight container overnight. Grind out any remaining beans between the burrs. (For an even more impeccable maintenance, vacuum out any remaining grounds and beans.) Rinse your hopper with warm water to remove any build-up of oils that will oxidize.


For your espresso machine, build in the following steps to every extraction. After removing the portafilter, flush the group head for 2 seconds to remove any grinds and oil residue on the shower screen. Wipe the filter basket before adding fresh ground coffee. After an extraction, make sure to remove the puck, flush the group head, wipe the filter basket before returning the portafilter to the group head. Never leave spent coffee grounds inside the portafilter for an extended amount of time.


At the end of the day, backflush your group head with espresso cleaner. If your cafe is very busy, you should backflush your group head between shifts, but with only water and no espresso cleaning. At the end of the day, make sure to brush your showerhead and wash your portafilter thoroughly.


Maintaining a strict protocol for your coffee extraction will not only extend the life of your machines, but you will also produce higher quality coffee that your customers can enjoy!


Mistake 3 - Incorrect Espresso Machine Brew Temperature


This next mistake in this series touches on a topic that can be very technical and advanced, but it does affect the quality of coffee your cafe is serving so it is worth a mention. This is the brew temperature in the Espresso machine.


In fact, there are many factors that affect the extraction of coffee during the brewing process. By using a good espresso machine certain variables such as brew temperature, flow rate and water distribution are kept constant and consistent allowing more uniform extraction over multiple brews. With pulling an espresso, the main variable that is used to control extraction is the grind size. This will not only affect the particle size distribution of the ground coffee but also the flow rate of water through the coffee bed in the portafilter. (We will be discussing grinder calibration in Mistake #5 of our series.) However, let only focus on brew temperature in this article.


On most espresso machines, the brew temperature can be adjusted by either directly changing the temperature of the brew boiler for dual/multi boiler machines or indirectly by changing the boiler temperature/pressure in heat exchange espresso machines. Generally speaking, there is a wide range of acceptable brew temperatures used in the coffee industry. For dark roast coffees, that range can be from 85-95 degrees Celsius. For Specialty Coffee, it is a narrower range of 90-96 degrees Celsius. For many of the heat exchange machines, the brew temperature may not be given. Even if it is given (for dual/multi boilers), it may not actually tell you the temperature of the brewing water but rather the temperature at the brew boiler.


The first step is to make sure that the temperature is within an acceptable range. If your cafe uses dark roasted coffee, a target of 90-91 degrees Celsius would be a good starting point. For Specialty Coffee cafes using medium to light roasted coffees, you should target 93-94 degrees Celsius. The temperature of the brewing water should be measured as water exits the showerhead. Maintaining these brew temperatures will help you to extract the most of your coffee without over extracting the negative flavours. This will put the focus on extracting an espresso that is sweeter and more balanced.


From the perspective of taste, espressos made with low brew temperature will come across as hollow, weak, and lacking sweetness. These espressos may also display high levels of acidity that is unbalanced and unpleasant. On the other hand, espressos extracted with brew temperatures that are too high will exhibit a harsh bitter taste that overpowers the sweetness in the cup. These espressos will tend to bring out the smoky, burnt aspect of the roasted coffee as well.


By starting with the right (and consistent) brew temperature, you will be able to find the sweet spot for your espresso. Using well-roasted high-quality coffee, the right temperature will make sure that your extractions are sweet, balanced, and full of flavour!


Mistake 4 - Not Testing Your Water Quality


Water makes up about 99% of your brew coffee and about 90% of your espresso. This makes water quality essential in producing high quality coffee in your cafe. But not only does your coffee beverage consists mostly of water, but your water quality will have an enormous impact on the extraction and flavor of your coffee. In addition, your water quality will have an impact on your espresso machine.


Whether the water in your city is hard (high TDS) or soft (low TDS), the first step is to make sure that the water is clean, clear, and free of odors and contaminates. Even if your tap water is safe for drinking, it may be treated with chemicals such as chlorine that would give an off-taste to your water. When this water is added to your coffee, it will result in the same off-taste in your coffee. It is advisable that all water that is used for making coffee be filtered using a micron filter and active carbon filter. This will provide you with clean, clear, odor- and taint-free water. As this should be done with all tap water, there is no measurement that needs to be considered in for this treatment. Other treatments will require you to measure the quality of your cafe water.


There are two factors you must consider for the water used in your espresso machine. If improper water is used in your espresso machine, you could have limescale buildup or corrosion in your machine. Low pH levels (high acidity) or chemicals such as chlorine can cause corrosion in your espresso machine. Water used for your coffee should have a pH of 7 (neutral) or as close to 7 as possible. pH can be measured by using a pH meter. Maintaining close to pH of 7 along with the filtrations mentioned above should help you avoid corrosion in your espresso machine.


Limescale is the build up of calcium carbonate in your water boiler, pipes and other parts of your espresso machine in contact with water. These buildups will cause blockages and improper functioning of your espresso machine. Calcium is a common mineral in water. An abundance of this mineral will increase the likelihood of limescale build up. The calcium in your water can be measured by using a titration kit which is measures Calcium as Calcium Hardness. In regards to limescale buildup, low Calcium Hardness would be preferred for your espresso machine, but as we will discuss below, Calcium also plays a role in the extraction of coffee flavors. Limescale buildup and corrosion should also be considered if you are using a water tower for boiling your brew water.


Besides maintaining your espresso machine, the taste of coffee served in your cafe should be delicious. The ability of your water to extraction the maximum deliciousness from your coffee is essential. There are two main components of water quality that needs to be considered for coffee flavor. The first is minerals, more specifically Calcium and Magnesium. Both of these are measured as Calcium Hardness. Calcium and Magnesium are found in water as ions. These ions help to extract positive flavors from your coffee. Without these ions, your coffee will taste flat with low aroma and unpleasant acidity. On the other hand, if too much of these ions are present, your coffee will taste harsh, chalky, and lack clarity. The SCA Water Quality Standard for Calcium Hardness is 68 mg/L (68 ppm).


The second component in the water that needs to be considered for coffee flavor is the Alkalinity (also known as a Buffer). The Alkalinity of your water can be measured using a titration kit similar to measuring Calcium Hardness. The Alkalinity "buffers" or moderates the acidity level in your coffee. It will help bring out the acidity of your coffee while making sure that it is not overpowering and sour. The SCA Water Quality Standard for Alkalinity is 40 mg/L (40 ppm).


Finally, the overall TDS (total dissolved solids) needs to be measured. Besides the Calcium Hardness and Alkalinity that would be a part of the TDS measurement, other dissolved solids may be present in the water. These may include other minerals such as Sodium and Potassium as well as anions (negative ions) such as Chlorides and Sulphates. These could contribute to off-tastes in the brew/espresso or even affect the extraction of the coffee. TDS can be measured using a Conductivity TDS Meter. The SCA Water Quality Standard for TDS is 150 ppm.


Water science for coffee is a complicated subject. If your intention is to maximize the water quality for your cafe, you can dive much deeper into the science behind water quality for coffee. Following the SCA Water Quality Standards will enable your cafe to maintain your espresso machines while producing delicious coffees, whether it is a pour-over brewed coffee or an espresso shot.


Mistake 5 - Not Dialing-In (Calibrating) Your Espresso


There are many factors that goes into controlling the extraction of the espresso in your cafe, but the most important variable is the grind size. (Majority of the other variables should be converted into constants.) Going back decades, most barista training consisted of adjusting the grind size of the coffee to meet a specific espresso brew recipe which includes the brew ratio (ground coffee to espresso ratio) and shot time. A common starting point for espresso is a brew ratio of 1:2 in 20-30 seconds. Even though Specialty Coffee has broadened the definition of espresso with a wider focus on the flavor of the espresso instead of just hitting the numbers, the general parameters of espresso have stayed pretty much the same.


Espresso dialing-in begins with your selected coffee and the filter basket in your portafilter. Filter baskets are designed for a specific amount (grams) of coffee. For double shot filter baskets, it is usually between 16-20g with the most common for Specialty Coffee being 18g. It is possible to put 1-2g above or below the intended amount (dose), but it is advisable to keep close to the manufacturer's specified amount. Once the dose is selected, a brew ratio is used to calculate the amount of espresso to be extracted from the coffee in grams. It is a good idea to start with a brew ratio of 1:2. So assuming you have an 18g filter basket, you will be grinding 18g of coffee into your portafilter and extracting 36g of espresso.


Then you will need to adjust the grind size to initially hit 25-27 seconds extraction time. Once you have accomplished this starting point, taste your espresso. From this point, there are several ways you can adjust for flavor.


The simplest method is to pull your espresso slight less or slightly more based on what you taste. For example, if your espresso, using the above recipe, produces an espresso that is too sour (high acidity), you should extract a bit more. This will help to extract more sweetness (and bitterness) and balance out the acidity in the espresso. You should take small steps by increasing the espresso weight by 2-3g at a time while tasting as you go. (Note that this will also increase your brew time.) On the other hand, if your espresso is excessively bitter, you should extract less by reducing your espresso by 2-3g at a time while tasting each shot. This will set the brew recipe for your coffee at your cafe. But dialing-in is not a one-time practice.


Dialing-in your espresso should be done at least once a day, and it's recommended that you do it once a shift, at the beginning of each shift. Due to changes in the roasted coffee, the ambient temperature and humidity, as well as the grinder burr temperature and condition, your espresso may extract differently from day to day or even during different times of the day. Therefore, you must be actively evaluating the brew recipe of your espressos and tasting them (whenever needed) to consistently produce the quality of espresso fit for service in your cafe.


Keep your espresso in control by dialing-in your espresso as often as necessary in order to produce the best espresso for your coffee drinks and your customers.


Mistake 6 - Not Tasting Your Espresso


This is the last mistake in our series, and by far the most important! Throughout this series the importance of tasting your espresso and making appropriate adjustments have been a common theme. Whether you are evaluating the state of your roasted coffee, keeping your equipment maintained well, using the correct brew temperature, testing your water quality, or dialing in your espresso, tasting your espresso should be at the heart of all these activities.


There are heaps of variables that will affect the taste of your espresso, and as much as you try your best to control all these variable, sometimes the quality of your espresso will be effected in undesirable ways. An improperly roasted batch of coffee or blunt burrs in your grinder or slight over- or under-extraction can cause your espresso to be inferior. Unfortunately, many times the only way to catch these differences is through tasting your espresso.


The first step in tasting your coffee is when your cafe receives roasted coffee - whether it is from an external supplier or your own roastery. You should have a very clear idea of how your roasted coffee should taste like. It is recommended that the first quality taste check of your roasted coffee should be done using a brewing method that lends to consistent extraction. Immersion brewing methods, especially using the SCA cupping protocol, is an excellent way to evaluate the taste of coffee while minimizing the variances that could occur from brewing. Even your espresso coffee should be evaluated this way for consistency of the roasted coffee.


Once the roasted coffee is approved, the espresso should be dialed in (calibrated). Espresso calibration should include dose in, espresso out and brew (extraction) time. A member of your team that is skilled in coffee sensory evaluation should be assigned to dial in each new batch of roasted coffee as well as maintaining the espresso taste everyday and even throughout the day. On a daily basis, only slight tweaks in extraction would be necessary. For more details on dialing in your espresso, check out our Mistake #5 of this series.


Your espresso is at the heart of coffee drinks served at your cafe. The taste and consistency of your espresso will keep your customers coming back. You should check the quality of every new batch of roasted coffee, and regularly dial-in and taste your espresso. Make sure that your espresso tastes great and is what your customers want, and wanting more and more!


𝑲𝒏𝒐𝒘𝑸𝒖𝒂𝒍𝒊𝒕𝒚 - 𝑩𝒓𝒆𝒘𝑸𝒖𝒂𝒍𝒊𝒕𝒚 - 𝑺𝒆𝒓𝒗𝒆𝑸𝒖𝒂𝒍𝒊𝒕𝒚


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