A scale built around pour-over recipes
The Hario Polaris combines weight and time measurement with ratio-based brewing assistance. Its Polaris mode calculates a target water quantity from your coffee dose and chosen ratio, then shows pouring progress as a percentage.
This overview is adapted from our existing equipment review, not a hands-on testing report. Specifications below reflect that source rather than independent measurements. Confirm the current CST-2000-B model and instructions before buying.
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Why consider the Polaris?
A basic scale tells you the load on its platform. Polaris mode adds recipe calculations: weigh your coffee, select a coffee-to-water ratio and use the calculated target to guide your pours.
This is especially relevant when a pour-over recipe is split into stages. Percentage progress can preserve a pouring structure when you change the overall brew size.
Key specifications
- Model: CST-2000-B.
- Maximum capacity: 2,000g.
- Source-listed resolution: 0.1g in the low range up to 300g, 0.5g through the middle range to 1,000g and 1g in the upper range to 2,000g.
- Ratio selection from 1:1 to 1:30 in 0.5 increments.
- Timer up to 9 minutes 59 seconds, with manual or automatic operation.
- Polaris and Classic modes.
- Automatic power-off after approximately five minutes when the timer is not running.
- Three AA batteries.
- Dimensions: 127 × 165 × 28mm.
- ABS resin, acrylic resin and silicone rubber; source-listed country of origin: China.
Check exact range boundaries and operating details in the manual. Display resolution is not an independently verified guarantee of accuracy, response speed or repeatability.
Polaris mode and water calculation
Choose the desired ratio and weigh your ground coffee. The scale calculates the corresponding total brewing-water target.
This removes a calculation from preparation, but it does not decide which ratio best suits your beans, grind or taste. Those remain brewing choices.
Percentage-based pouring
As you add water, the scale can show progress towards the target as a percentage. A recipe divided into equal stages can therefore be followed through cumulative percentage targets rather than recalculating each stage in grams.
If you change the coffee dose while keeping the ratio and stage structure, the percentage approach can help carry that structure across brew sizes.
Recipe scaling still requires judgement. Changing brew size may affect flow, bed depth and brew time, so repeating percentages is not a guarantee of identical extraction.
Automatic and manual timing
The source describes automatic timing triggered by the weight change when pouring begins. Manual operation is also available.
Check the mode sequence before brewing and use manual control if that better suits your recipe. We have not independently tested the trigger response.
Classic mode
You do not need ratio guidance for every task. Classic mode hides the ratio, target-water and percentage information, leaving conventional weight and time readings.
This can be useful when a recipe is already written entirely in grams, or when you simply want to weigh coffee without following the Polaris workflow.
Pour-over focus
The Polaris is especially relevant to V60 and other manual pour-over methods, where dose, water target, timing and staged pours commonly work together.
Its 127 × 165mm footprint is larger than the compact Exagram scales. Check that your vessel rests securely and that the complete brewer, vessel, coffee and water remain within capacity.
Understanding variable resolution
The scale does not maintain a 0.1g display interval throughout its full range. The listed intervals become coarser at higher loads.
Account for the equipment resting on the platform rather than assuming a zeroed display removes its physical load. Tare makes ingredient measurement easier, but does not increase the maximum supported weight.
AA battery power
The Polaris uses three AA batteries rather than USB-C rechargeable power. The source review records supplied batteries intended for testing; confirm the current package and keep replacements available.
Choose according to your preferred routine: replaceable batteries avoid a charging step, while a rechargeable scale avoids routine disposable-battery replacement.
Polaris versus Exagram Pro
The Wacaco Exagram Pro combines a compact footprint, USB-C charging and dedicated espresso and pour-over modes.
The Polaris places greater emphasis on pour-over recipe management through target-water calculation and percentage progress, with a larger footprint.
For espresso-machine use, measure tray and cup clearance carefully. A compact espresso-oriented scale may fit that requirement better than the Polaris's pour-over-focused format.
Polaris versus standard Exagram
The standard Exagram provides a simpler weighing-and-timing approach with AAA batteries. Check version-specific automatic timer features when comparing.
The Polaris adds a different recipe workflow rather than establishing superior weighing accuracy. If you will not use ratio calculation or percentage-based pouring, a simpler scale may cover your needs. Compare current prices rather than relying on a fixed price difference.
Who is it best for?
Consider the Polaris if you regularly brew pour-over, work with ratios and staged pours, vary your coffee dose and would use automatic target calculations.
Its Classic mode also lets you step back to normal weight and time readings when the additional guidance is unnecessary.
Who should look elsewhere?
If all you need is a weight display and timer, the recipe functions may add little value. Buyers prioritising compact espresso clearance, rechargeable power or longer timing should compare those requirements first.
The maximum timer recorded in the source is 9 minutes 59 seconds. Do not assume it can cover longer continuous timing simply because the scale offers advanced recipe functions.
Does Polaris mode make better coffee?
Not automatically. It can make quantities easier to calculate and a recipe easier to record, but cannot choose a suitable grind, water temperature or pouring technique.
Its practical value is helping you measure experiments and repeat a successful structure. You still assess the cup and decide what to change.
Care and ownership
Follow Hario's cleaning and liquid-exposure instructions. A scale used around brewing water should not be assumed waterproof, and the battery compartment needs protection.
Allow for platform stability and reading visibility as well as dimensions when arranging your setup.
Our take
The Polaris has a clear reason to consider it beyond basic weighing: ratio-based target calculation and percentage progress for pour-over recipes.
Those functions may help a methodical brewer adapt and reproduce recipes. They are unnecessary if you prefer a simple grams-and-time workflow, and we have not tested accuracy or detection performance for this overview.
Check current price on Amazon UK →. Confirm the model and current specification.
Develop your pour-over routine
Explore our Pour-Over Perfection digital guide, or start with The Complete Beginner's Guide to Home Coffee.