1. Thin espresso
If you notice that your machine is producing thin, oily, or watery shots, something is not right. Firstly, check the production date on the coffee beans – if they were roasted and sealed over three weeks prior, it will lack viscosity. Also check the extraction yield and/or brew-ratio of your espresso, plus the temperature of your machine as both can contribute to thin espresso. Speak to your roaster about an ideal recipe and temperature to brew.
2. Thick, bubbly crema
Coffee that is too fresh will present a thick, bubbly crema as it is still releasing carbon-dioxide from the roasting process. You may be able to 'air' the bag and release more gas before serving, but your best bet is to speak with your roaster about the ideal time to brew as well as the shelf life.
3. Slow production
This comes down to having adequate systems in place. Consult with your team and implement an operational plan for your staff to follow from ordering through production to delivery. A good flow as well as regular training will keep those quality brews coming out like clockwork and, most importantly, keep your customers happy!
4. Water filter issues
Did you know that more problems are caused by dirty machines than actual broken parts? The build-up of scale in commercial coffee machines is an expensive problem, and will require replacements. Make sure you are using the correct type of filtered water in your machine and conduct regular servicing to avoid these problems. Always keep the number of your coffee machine manufacturer and roaster handy for last minute emergencies. Also, ensure your staff know to call you at any time if there is an issue – panicking and trying to fix the machine can often cause more damage than good.
5. Stale or expired coffee
As tempting as it can be to store your coffee beans in clear displays, the air and sunlight will compromise the taste of your coffee. Preserve your beans in a cool, dark place in an airtight container to prevent them from spoiling. This will also allow you to properly clean out the hopper, removing any build-up of oils or other fine particles. This can be done easily with the steam wand on your coffee machine at the end of each day, no detergent required. Just make sure the hopper is dried well before placing it back on top of the coffee grinder.
6. Incorrect dosage
Dosage refers to the amount of ground coffee that goes into each shot. Dosage will vary depending on your particular beans, your water pressure, weather conditions and your basket size (usually between 18-23 grams). The skill of a barista lies in adjusting the coarseness of the grind and the dosage to achieve the coveted 28-second shot. If your shots are running too short, your coffee is likely under-extracted and will leave a sour aftertaste at the back of your tongue. It may mean there's too much coffee or it's too tightly packed/fine, so adjust your grind and/or dose accordingly. If your shots are running too long, your coffee is probably over-extracted or "burnt" and will leave a bitter taste at the front of your mouth. It may mean there's not enough coffee or it's too coarse and the water is running through too quickly. Again, make some small adjustments to your dose and grind until you get back to pouring the perfect cup. The other thing to watch for if your shots are perfect but the coffee still tastes weak, it may be as simple as switching to a slightly bigger basket size, allowing more coffee into each shot.
So once you've dialled everything in and fine-tuned your recipe for the perfect cup, the real challenge lies in replicating that recipe consistently between different staff members, changing weather conditions, a fresh batch of coffee, and so on. If you have more than one person putting on shots, make sure everyone tamps with the same pressure. Teaching correct tamp technique will help, but to eliminate any variances, you might want to consider investing in an electronic Puq Press. Milk temperature is another factor that can vary widely person to person. A simple thermometer or temperature-monitoring jug will do the trick. Then of course the coffee itself can behave differently, depending on factors like changing humidity in the air, and the 'age' of the coffee after roasting. The best way to maintain consistency is to go back to basics and check your shots regularly throughout the day, as the temperature changes, you open a fresh bag of beans, at change of shift, etc.