cafesing owl espresso scale

OWL G1 Espresso Scale Design Review

1 Why Need Espresso Extraction Data?

Many weekend baristas like to make espresso at home, and most use a semi-automatic espresso machine or hand-pressed espresso makers; it is vital to have an espresso scale, because the data can accumulate experience. Once you have got a certain amount of coffee brewing or espresso extraction data, you will have a certain amount of coffee-making wisdom.

 cafesing owl espresso scale

2 How to Make Espresso Scale "Simple"?

I have used many coffee scales. Some scales have many functions and icons, which are confusing and difficult to operate; some have poor accuracy and data drift jumping; some cannot be easily placed under semi-automatic or hand-pressed espresso makers, causing operating trouble; some auto-timing function is unsuitable for pulsing drip of hand-pressed espresso makes, etc. I think those are interference caused by the coffee scale, which will tie me up during making espresso, and complicate the extraction process and result evaluation.

According to my design philosophy, the principle of SIMPLICITY is the first priority. During the espresso-making process, if we can build the scale to a suitable size for easy placement, and at the same time let the scale display stable and accurate measurement data, then espresso extraction will become more simple, and people will be more immersed in brewing coffee activities.

In the espresso-making time of about 30 seconds, the operator is prone to various misoperations caused by being in a hurry. If there is an intelligent assisted driving mode similar to Tesla Autopilot, which can be adapted to different types of espresso machines (semi-automatic, lever, and hand-pressed espresso makers), further reducing operator workload to reduce misoperation of scale. Those smart modes measure and monitor data more easily, which makes espresso extraction more simple.

To sum up, for me, a "simple" espresso scale is the right combination of Performance × Size × Mode. Respecting the operator’s espresso-making habits, letting people operate the scale and monitor and record the extraction data of coffee brewing becomes more simple, while causing no or fewer new problems.


3 How to Design "Simple" Espresso Scale

3.1 Performance

Performance = Accuracy × Stability; this is a set of trade-offs. If the accuracy is designed to be too high, a lot of subtle noise will inevitably be received during the measurement process. In addition, if the algorithm cannot reach a certain level, the display of measurement data will be unstable.

The sensor we selected and the algorithm we designed achieved an accuracy of 0.1g, which is enough for espresso-making. But how to keep the stability of the measurement under 0.1g accuracy? The simple way is to choose a rigid all-metal material to make the scale shell, because algorithm optimization requires time and experience accumulation; rigid materials can reduce disturbances and improve measurement stability without complex algorithms.

We finally chose high-quality aluminum alloy for the shell, internal support, and weighting pan of our Espresso Scale.


3.2 Size

Size = Small × Thin. Plastic materials cannot be made thin under minor restrictions. Making them smaller requires reasonable design of internal sensors, circuits, components, batteries, etc. However, if plastic is made too thin, it will easily break. At the same time, the lack of rigidity of plastic will cause more noise disturbance during measurement. 

Consistent with the above choices of performance design, I chose rigid aluminum alloy materials to make the scale shell and internal structure, which can be made thinner and smaller than plastic.

 cafesing owl espresso coffee scale

3.3 Separation Design

After choosing aluminum alloy to make the outer shell and internal structure of the scale, we discovered a new problem: the display area and button area cannot be made of metal materials and are generally made of ABS material.

If we build the weighting pan, display area, and button area together, due to the inconsistent density of metal and ABS, I think it will affect the stability of the data during measurement. At the same time, the weighting pan will be disturbed when operating the buttons. Therefore, we chose a design where the scale pan is independent and separated from the display area and button area.


3.4 Mode

When we make espresso, we do a lot of operations on the scale, such as the coffee cup tare, timing the extraction time, etc. First, add intelligence to these manual operation functions of the scale (Tare, Timing, Stop Timing, Freeze Data).

a. Intelligent Tare: Intelligently determines whether it is fluid or a solid, and tare only after identifying the solid item. If solids are placed on the weighing pan in sequence, then auto-tare in sequence (e.g., put the pad first and then the cup), and the automatic timer will not be triggered.

b. Intelligent Timing: Intelligently recognizes that the liquid is not solid and has gained weight, then automatically starts the timing.

c. Auto-timing Lock: Only after manual unlock, then enter the pending state of auto-timing; it is convenient to perform other hand operations before automatic timing, such as checking the weight of beans and powders, and manual tare.

d. Intelligent Stop Measuring 1: Intelligently recognizes that the liquid does not gain weight, then automatically stops timing and weighing. It is suitable for semi-automatic espresso machines that are continuously drip liquid.

e. Intelligent Stop Measuring 2: Intelligent recognition of sudden weight loss, automatically stops timing and weighing. It is suitable for hand-pressed espresso-makers with pulsing drip liquid, and pour-over coffee brewing.

f. Intelligent Data Display: Intelligently capture the time and weight data of espresso when the data measuring is stopped, and display to facilitate people to record data.

Then combining these intelligent functions into an intelligent assisted mode, during espresso-making, reduces the operator's workload and misoperations, and decreases the cost of learning functions.

3.4.1 Mode-E1

Put these functions of Intelligent Tare + Intelligent Timing + Intelligent Stop Measuring 1 + Intelligent Data Display into full assist Mode-E1. Under Mode-Espresso1, there is no need to do any manual operation on the scale, which is very suitable for semi-automatic espresso machines.

The general process is that, the cup is automatically tared when placed on the scale, and the dripping sensor automatically timing. When the espresso fluid dripping is stopped, auto stop timing and weight measurement. The extraction time and weight numbers will remain stationary, making it easy to record the data.

cafesing owl espresso scale

3.4.2 Mode-E2

Put these functions of Auto-timing Lock + Intelligent Timing + Intelligent Stop Measuring 2 + Intelligent Data Display into semi-assist Mode E2. Under Mode-Espresso2, you only need to hand tare and unlock auto-timing, and everything else is automated, which is very suitable for hand-pressed espresso makers and hand drip.

The general process is that, put the cup on the scale to hand tare, manually open the auto-timing lock, and the liquid dripping sensor will auto timing; when the coffee liquid still drips, you can remove the cup to stop the timing and weight measuring; the extraction time and weight numbers will remain stationary, making it easy to record the data.

cafesing owl espresso scale

3.4.3 Mode-H

Of course, we have also released the manual mode, Mode-H, which is entirely controlled by hand and has no intelligence.

  Mode-Espresso1 Mode-Espresso2 Mode-Hand
Weigh-Tare Auto Manual Manual
Timing+Weigh Auto Lock + Auto Manual
Stop Measuring Auto Auto Manual
Data Display Auto Auto Manual


4 OWL Espresso Scale

We followed SIMPLICITY design concept, made the espresso scale smaller and thinner with all aluminum alloy materials, achieved a stable measurement accuracy of 0.1g, redesigned the auto functions and combined these into the intelligent mode, and finally designed the innovative product OWL Espresso Scale.

We aimed to make the "simple" devices for the weekend barista. I hope they will continue to be immersed in making craft coffee, appreciate coffee passionately, and look forward to the gifts of nature. I hope you'll enjoy our OWL Espresso Scale.

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