Acaia Pearl Model S Coffee Scale

Before using the Acaia Pearl Model S for the first time, select a stable, vibration-free, and level surface. The Pearl Model S is designed primarily for pour-over brewing and is larger than the Lunar — place it on a counter or scale mat clear of drips and splashes. Avoid placement near heat sources, strong drafts, or other equipment that could affect readings.

Charge the scale before first use using the included USB Type-C cable with a standard USB charger (5V/1A output, or a USB-C PD charger supporting 5V). Do not use fast-charging adapters exceeding this specification. A full charge from empty takes approximately 3–4 hours. Once fully charged, the scale provides up to 16 hours of use at normal brightness or up to 40 hours in low-brightness mode. The Pearl Model S has charging protection: if the scale is hot from brewing, it will not charge until it has cooled — this is normal.

To power on: tap the Power button. To power off: double-tap the Power button. On first use the scale starts in Weighing Only Mode, displaying [ 0.0 ] in grams. To switch between grams and ounces, press and hold the Tare button.

To check battery level: with the scale off, press and hold the Power button. The display will cycle through [ acaia ], then [ Settings ], then show the battery percentage. Release to return to normal.

To calibrate: switch to Weighing Only Mode and set units to grams. Rapidly tap the Tare button until [ CaL ] appears on the display. Place an Acaia or F2-class calibration weight (100g, 500g, 1000g, or 2000g) in the center of the weighing pan and wait until the display shows [ _End_ ]. Calibration is complete. Recalibrate periodically or after the scale has been moved or subjected to impact.

To pair with the Acaia app (iOS or Android), ensure Bluetooth is enabled in the scale settings (default: On), then open the app and connect. The app is required to use Brewguide Mode and to update firmware.

Understanding the Nine Modes

The Pearl Model S has nine modes. With the scale on, press and hold the Power button to cycle through active modes. Only modes enabled in the Settings menu will appear in the cycle. By default, Weighing Only Mode and Dual Display Mode are on; Brewguide Mode is on; all others are off and must be enabled in Settings before they appear.

Mode 1 — Weighing Only Mode

Displays weight only (0.1g readability). Use for dosing coffee, measuring water, or any task not requiring a timer. Tap Tare to zero. Press and hold Tare to switch between grams and ounces.

Mode 2 — Dual Display Mode

Displays timer (left) and weight (right) simultaneously. Tap Power to start, stop, or reset the timer manually. Tap Tare to zero weight. The timer auto-stops when the container is removed for the number of seconds set in the Timer Auto Stop on Cup Removal setting (default: 10 seconds).

Mode 3 — Pour-Over Auto-Start Timer Mode

Designed for pour-over brewing. The timer starts automatically the moment the scale detects the first flow of water, and stops when the brewing vessel is removed. When the vessel is removed, the display flashes the final beverage weight. The mode auto-resets after the Timer Auto Reset delay (default: 20 seconds). Enable this mode in Settings before it appears in the mode cycle.

Mode 4 — Portafilter Mode

Place an empty portafilter on the scale — it auto-tares the portafilter weight and displays [ 0.0 ]. Remove the portafilter once the loading icon disappears, fill with ground coffee, then replace to read the dose weight. The mode auto-resets 15 seconds after portafilter removal (adjustable). Enable in Settings.

Mode 5 — Espresso Mode

Place a cup (2g or heavier) on the scale — it auto-tares. When espresso flow is detected, the timer starts automatically and stops when flow stops. When the cup is removed, the display flashes between the beverage weight and the vessel weight. If idle for 10 seconds with no weight or flow detected, the mode resets automatically. Enable in Settings.

Mode 6 — Flowrate Mode

Displays timer, weight, and real-time flow rate (in g/s) simultaneously. Designed for pour-over brewing where visualizing pour consistency matters. Tap Power to start/stop the timer. Enable in Settings.

Mode 7 — Flowrate Practice Mode

A dedicated practice tool for improving pour consistency. Displays current flow rate on the left and a stability indicator bar on the right — each dot represents 0.5 g/s. Use this mode to train a steady, controlled pour. Enable in Settings.

Mode 8 — Brewguide Mode

A step-by-step interactive brewing guide. Use the Acaia Brewguide app to scan a QR code on a coffee bag or browse guides from roasters worldwide, then upload a recipe to the Pearl Model S. The scale walks you through each brew step on the display. Tap Power to redisplay the current instruction. Press and hold Tare to advance to the next step. Brewguide Mode only operates in grams.

Mode 9 — Countdown Mode

A customizable countdown timer with 3 adjustable presets and 30+ ringtone options. Press and hold Tare to set the timer duration; tap Tare to increase the value. Tap Power to cycle between presets. Press Tare to start/stop the active countdown. The timer continues counting in negative values after zero by default (adjustable). Enable in Settings.

Sound Notifications

The Pearl Model S can announce weight and time audibly. In Settings, set Timer Notification Sound to Voice (reads time every 10 seconds) or Sound (beeps at 10s and 60s intervals). Set Weight Notification Sound to Voice (announces weight when stable and every 20g during brewing) or Sound (beeps every 20g). Both are Off by default. Adjust volume (1–5) in Settings.

Settings Menu

With the scale off, press and hold the Power button until the display shows [ acaia ] then [ Settings ]. Release to enter. Tap Tare to navigate, press and hold Tare to enter a setting and confirm a selection. Double-tap Power to exit Settings and return to modes. Key settings include Brightness, Sound Notifications, Volume, Default Unit, individual mode on/off toggles, Sleep Timer, Battery Saving, Weighing Filter, Zero Tracking, Weighing Resolution, and Bluetooth. To factory reset: navigate to Reset to Default → Yes.

Routine Cleaning After Each Use

Wipe the weighing pan and scale body with a soft, slightly damp cloth after each session. The Pearl Model S is splash-resistant but not waterproof — do not submerge it or allow water to accumulate near the buttons or charging port. Dry thoroughly after any contact with moisture.

Cleaning Products to Avoid

Use warm water only on a soft cloth. Never use detergents, alcohol, bleach, or abrasive cleaners. These will damage the anodized aluminum surface finish and may compromise the scale's electronics.

Weighing Pan

The weighing pan can be removed for cleaning. Lift it carefully off the scale body, rinse under warm water, and dry completely before replacing. Ensure it is properly seated flat before weighing.

Charging Port

Keep the USB Type-C charging port free of coffee grounds and moisture. If grounds or debris accumulate in the port, use a dry brush or compressed air to clear it. Never insert metal objects into the port.

Long-Term Storage

If storing the scale for an extended period, charge the battery to approximately 50–80% first. Store in a cool, dry location away from direct sunlight and extreme temperatures. Avoid stacking heavy objects on top of the scale, which can damage the load cell.

Scale Won't Turn On

Connect the USB Type-C cable to a 5V/1A charger and allow the scale to charge for at least 15–20 minutes before attempting to power on. If the battery was fully depleted, it may need a short charge before it will respond. Confirm the charger is working and the cable is fully seated.

Scale Not Charging

The Pearl Model S will not charge if it is hot from recent brewing use. Wait for it to cool completely and try again. Confirm your charger outputs 5V/1A (or a USB-C PD adapter supporting 5V). Fast-chargers and charging hubs delivering higher voltages may not charge the scale.

Timer Not Starting in Auto-Start Modes

Pour-Over Auto-Start Timer Mode and Espresso Mode must be enabled in the Settings menu before they are available. Once enabled, ensure the container is placed on the scale first and allowed to stabilize before beginning your pour or extraction. In Pour-Over mode, the flow must be at the scale surface level — if pouring from a significant height with a fine stream, detection may be delayed. In Espresso Mode, the cup must weigh at least 2 grams for the auto-tare to trigger.

Inaccurate or Unstable Readings

Place the scale on a completely flat, stable surface away from vibration, air currents, and heat sources. Recalibrate in a stable environment using an Acaia or F2-class weight. Check the Zero Tracking setting — Acaia recommends 1D for the Pearl Model S. If using a pour-over setup, ensure the carafe or server is fully stable and not wobbling on the scale. Adjust the Weighing Filter setting: Normal or High provide more stable (but slightly slower) readings than Sensitive.

Modes Not Appearing When Cycling

Only modes that are enabled in the Settings menu appear in the mode cycle. To enable a mode (e.g. Espresso Mode, Portafilter Mode, Pour-Over Mode), enter Settings (power off, hold Power button), navigate to the mode's setting, and set it to On.

Brewguide Not Working

Brewguide Mode must be enabled in Settings and requires the Acaia Brewguide app paired via Bluetooth. Ensure Bluetooth is on in both the scale settings and your phone. The recipe upload from app to scale can take up to one minute. If the scale still doesn't receive a recipe, force-quit the app, reconnect, and try again. Brewguide only operates in grams.

Sound Notifications Not Working

Timer and Weight sound notifications are off by default. Enable them in Settings under Timer Notification Sound and Weight Notification Sound. Check the Volume setting — if set to Off, no sounds will play. Sound notifications in specific modes require the Weighing Filter firmware version supporting audio (version B).

Warranty and Support

The Acaia Pearl Model S carries a 2-year manufacturer warranty. For warranty claims or technical support, contact Acaia directly at support@acaia.co.