Scales in the coffee industry have become more of a staple with the rise of pour over brew in cafés and the growing interest in craft brewing at home. It is no secret that a scale is a useful tool that can improve your daily cup, but scales are sensitive precision instruments that do require a little attention to maintain. There are a lot of aspects to the weighing process that can easily be overlooked. What types of scales are there? Which scale is best for your application? How do you care for your scale? Most importantly, is your scale consistently accurate?
We want to dig into these questions a little and review what makes scales work, the importance of weighing coffee and water when brewing, how to pick the right scale for you, and how to make sure your scale is giving you accurate and consistent readings. A little knowledge can go a long way and save you time, money, and precious coffee beans.
The most commonly used in general practice are load cells. A strain gauge load cell (stay with me) is what most at-home and light commercial scales use. They consist of an aluminum bar with sensors attached that measure the slightest bend in the bar from weight or mass pushing from above. In less expensive scales, the shape of the load cell is an "I", in higher quality scales, such as our scales at Brewista, the load cell is an "H" shape, so readings remain accurate despite corner loading. The sensors on each end of the "H" detect tensions and compression within the small aluminum bar and give a reading to the scale display based on how far they have moved in relation to each other. Weight changes happen instantaneously and we are able to weigh things quickly and easily with this technology.
First, one woman's tablespoon might be another woman's heaping tablespoon, and "scoop" is not an amount as far as we are concerned. Even if you level your "scoop" or TBS and use, say three, in your daily brewing, that can vary widely in weight, and result in a different cup every time you make coffee. Light and dark roast beans aren't all the same density, so weighing the grounds will let you have the same actual amount every time.
The inconsistency multiplies when you are not weighing your water. Coffee is two ingredients, both needing to not only to be fresh (and beans ground to the right coarseness), but also to exist together in a ratio that works and can be duplicated. A 17:1 ratio of grams of water to coffee is a widely used recipe, but you might like yours better at 15:1 or a little mellower at 19:1. If you pick a ratio and use it while brewing, you can zero in on your perfect cup, and easily repeat it as a part of your daily routine instead of stumbling upon that occasional amazing cup of coffee that you eyeballed half awake and can't repeat.
Weighing your ingredients gives you a solid base to go off of and allows for reliable replication of your recipe. If you're eyeballing your coffee and water every morning and you are a 16:1 kind of coffee drinker, you only hit that sweet spot twice a week. If you aren't measuring, you're most likely wasting some of those expensive locally artisan-roasted beans with inconsistent batches.
If your café is in the middle of a morning rush and the barometric pressure is rising as the day warms up, you'll need to constantly dial in your grinders to keep those delicious espresso shots pulling perfectly. Inaccurate readings from your scale are not what you need.
Scale load cells are a form of transducer, which means they are "transforming" the mass into an electric signal that tells you how much something weighs. Those electric signals need good reception, or a good power connection, so even the wires within the scale are important. Weighing with a badly made scale is like trying to call someone from the basement of a concrete building. It doesn't work too well. Understanding the basics of scales and how they work will help you know how to take care of your scale.
Electromagnetic disturbances can affect scales. If your phone is right next to your scale, make sure you give it a little bit of table space. It is possible to store a scale sideways, but this requires them to be zeroed out before every use.
The number one issue people have with their scales is power trouble. Make sure you have fresh batteries or a stable secure connection to the wall outlet if you have an adaptor/plug-in type. Scales also need to be used at room temperature. Since the load cell or springs are made of aluminum, scales can be sluggish if really cold and not give you accurate readings.
Do you want the portability of a battery operated scale or the stability of a plug in scale? How heavy and large are the items you will be weighing? Is the loading platform on the scale big enough to handle your daily tasks? If you are going to be weighing on an espresso machine or in a busy café, a water resistant scale might be best for you.
Once you've picked one out, read the manual, learn what it can do for you, and play around with it to get familiar. After a week of use you will never want to go back to estimating the fine craft we call coffee. Getting a well-made scale, perhaps made by Brewista, will ensure you years of reliable use.