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Has an industrial grade (read: super accurate) scale shoehorned inside.
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Visual real time pour guide indicators are a boon for anyone looking to control the flow rate of their pour over brews.
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Guided beverage mode is improved over the previous Pearl model and actually useful.
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Very water resistant, since the scale is built “upside down” compared to other scales. Not submersible though.
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The readability of the scale is increased dramatically over the previous Pearl model, and most modes display 0.1g readouts.
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Battery seems to last forever, and the USB-C charging is much faster than the previous Pearl model.
The Acaia Pearl 2021 comes in a nearly identical package to the original Pearl Scale. It’s a cardboard box with an outer paper sleeve, and it has a very Japanese kind of feel to the packaging. The sad news here is, Acaia is still using EPE dense foam (laminated closed cell packaging foam) as the main protective shell for the scale. They, like every social conscious company in coffee and espresso, need to move to fully sustainable and environmentally friendly packaging.
Once you remove the outer sleeve and take the lid off, you’re greeted by a getting started manual. Remove that and you see some nifty Acaia stickers. Lift those off, and the top thin layer of EPE foam and you see the scale, wrapped in protective plastic on top.
Take the Pearl out of the EPE foam cocoon, and you next find the protective heat mat, which is an integral part of the Pearl scale. Underneath is a USB-C charging cable.
There are two cardboard inserts in the bottom of the Pearl scale to protect its sensitive weight sensors during travel; these teal blue inserts should be removed before first use. On top of the scale is a peel off plastic protective cover that reminds the user to always use the silicone heat mat when placing hot objects on the scale.
The scale measures 16cm square, and sits 3.2cm tall. It very much looks like the Apple Time Capsule from 2012. We have the all white version, but there are two black versions: normal black (with clear plastic sides) and pure black, with black coated sides.
The scale’s maximum capacity is up to 2 kilograms now, a welcome boost. Out of the box, the scale displays 0.1g readings up to 1kg, and in 0.5g increments from 1kg to 2kg, but you can change this in the advanced settings so it displays 0.1g increments through the entire scale range.
The scale weighs just over a pound (500g), and has a 1100mAh lithium ion battery. The charger is USB-C and much faster than the previous mini USB charging system. It does not include a charger, but does include the USB-C cable.
The scale’s display has lots of hidden indicators beyond the two visible soft touch buttons. Here is Acaia’s layout from their product manual, showing all the extra indicators and number positions.
The Pearl 2021 scale has five distinct modes, though only two (Weigh and Dual Display modes) are enabled out of the box. Each mode is accessed by a long press on the power button. If you want access to all five modes, or want to select which modes you want on or disabled, these can be set via the scale’s advanced settings.
The five modes are:
Five stage walkthrough for brewing pour over coffee. Stages include: adding cup, adding filter, adding coffee, pouring brew water, removing filter. Timer stops when you remove the filter. Calculates total brew time, beverage weight, brew ratio. Mode also displays flow rate indicators (disabled out fo box).
Of note, the previous Pearl Scale had an ‘espresso mode’ that has been removed from the Pearl 2021 model.
The amount of settings you can do to the Pearl Scale are staggering. They include, but are not limited to
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Sleep Timer
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Brightness Setting
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Battery Saving Mode
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Key Sound Settings
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Weight Filter Setting
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Turning on or off the main modes individually
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Weighing Resolution, High, Low, Precise
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Bluetooth Setup
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Flow Rate Indicator Display
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Weight Stability Setting
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Auto Reset Time
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Portafilter Auto Reset Time
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Full System Reset
What’s New on the Acaia Pearl 2021
Acaia pretty much rebuilt this scale from the ground up for 2021, though the main body and casing is the same. Here’s some of the major and minor changes from the previous Pearl scale.
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New and better industrial calibre scale mechanism inside
More Accuracy
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Changed from Micro USB to USB-C connector and charging, which is much faster.
It's About Time!
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1100mAh battery, delivering 30 hours of continuous use, with bluetooth enabled
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Real Time Flow Rate Indicator
Best New Feature
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Starts registering at 0.5g but can be adjusted to 0.1g via advanced settings
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Most modes including timer modes now display 0.1g resolution
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Beverage Mode improved to include brew ratios
Best New Feature
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Maximum Capacity increased to 2,000g
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Much faster response time than previous scale
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Brighter scale readout, more options for tuning it up or down via advanced settings
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Graphical icons used for scale modes (previous version used yellow and green lights)
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Visual fades of display when switching modes
Undocumented Feature
The price has gone up $10 from the previous Pearl’s last price (it is now $150USD). Considering the original Pearl in 2014 was $130, a $20 price bump in 10 years is pretty good, especially with the new modes, larger battery and faster charging.
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There are two setup things you should do with the Acaia Pearl before using it. First, charge it to full capacity, then pair it with your smartphone and the Acaia apps (which you may or may not want to do – read on later in this review). Once this is done, the scale is ready to go, with two of its five modes enabled, and the other three modes ready to enable if you go into the scale’s advanced settings. There’s also some customization you can do via the Acaia Coffee app. The scale itself can also be modified by accessing the advanced settings menu built into it.
Powering the scale up, I did notice the display is brighter than the previous Pearl model. It was on a sunny counter and I had no problems reading the display. When put next to the old Pearl model, the difference is noticeable. This display brightness can now be adjusted in the settings menu.
The scale powers up very quickly. The legacy Pearl would take about 1-2 seconds to fully power on and show a zero tare reading. The new Pearl 2021 has this time to about 0.4sec or faster.
As mentioned above, only two modes are enabled out of the box: the Weigh and Dual Display modes. Acaia does this because they assume many users of this scale might not want the hassle of cycling through so many modes. I, on the other hand, love the hassle, so I dove into the advanced settings (you can do so by pressing and holding the power button until the display reads SET), and enabled all five modes for the scale.
Cycling between the modes is relatively easy: it’s a long button press until the display changes to its next mode. A nice new feature on the Pearl 2021 is how the display fades and brightens when changing modes. This is a good visual indicator if you turn off the beep sound.
(NB, we have reshot the video below, to better display the Pearl 2021’s bright display. Apologies for the poor video, it will be replaced in a few days)
I quickly gravitated towards using two modes: the Dual Display mode, and the Beverage mode (which is much improved on the Pearl 2021). I like using the Dual Display mode because that is the first mode that uses Acaia’s new visual flow rate indicator lights. This, along with the Beverage Mode, have turned out to be this scale’s killer features.
The flow rate indicator lights are little solid circles that light up as you pour your brewing water. More lights that glow mean a faster pour. The indicators register as low as 0.5g a second pour times, and max out at 11g/sec. There’s two sweet spots indicated by larger solid circles, one set at 2.5g/sec, and the second set at 6.5g/sec. Keep your water pouring between these two indicators and you’re sweet as gravy. Here’s Acaia’s manual display of the indicator lights and their range.
The Beverage mode is very much improved over the previous Pearl Scale, though how you press the buttons to advance between steps has changed. On the previous Pearl, a quick tap of the T button advances to the next step. On the Pearl 2021, you have to press and hold for a half second until the display updates and moves onto the next step. It took me a bit of time to get used to this. If you get it wrong, you basically screw up your beverage mode and have to start over. You can see the “action” in the mode video above.
Lastly, I did try to connect the scale to the Acaia Coffee app on my Google Pixel 7 Pro smartphone and the app would “see” the scale, but it would not register any action from the scale, like the timer or weight. I ended up connecting it to a Huawei P10 and Google Pixel phone from 2016, and managed to update the scale’s firmware via the original Pixel device.
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The Acaia Pearl 2021 model is a marvellous scale, only let down by its current app experience. I keep harping on that because the connected app experience was one of the biggest initial selling points for the scale, but it has not kept up with the dream or hype since then. More on that later.
On its own, without the apps, the Pearl 2021 is amazing, and remains the scale that sets the upper bar for what coffee scales could be. Fast start up time, hyper-accurate hardware inside, bright display, and all those modes.
The visual flow rate indicator is the number one killer feature on this scale. It is a tool you never thought you needed, but once you have it, you cannot do without it. I truly believe it has improved my pour over coffee by training me to be more steady and even with my pouring flow rate for pourover coffee. When I use other scales, I miss the functionality.
When trying new coffees, I always gravitate towards the Beverage Mode, because I’ve discovered different roasts and different bean types will result in slightly different brew ratios as they absorb more or less brewing water. This is something that would have taken me a lot of brain horsepower and secondary recording and writing to figure out otherwise.
The Beverage mode has also become a tool I use in evaluating coffees. I have set parameters and brewing times, and the stages in the beverage mode, along with the finalized readings allow a certain consistency I struggled to have previously.
The Pearl lasts forever between charges. Ours gets used every single day, often multiple times a day, and I can go months between charging. When I am testing equipment and using the scale for several hours, it may last 20-30 days before needing its next charge. And charging is quicker than the previous Pearl model (by about 35%), though still quite slow by USB-C standards: my Pixel 7 Pro phone charges in about 65 minutes from near empty; the Pearl 2021 takes about 3.5 hours to charge its lithium ion battery that’s have the mAh rating.
One of my favourite undocumented things about the scale’s usability is how the display fades and brightens between mode changes and when powering off. The beep is a bit annoying after a while (especially if you use the scale for several hours), but you can turn the beep off and rely on the display fade as a nice silent indicator that your button presses have been registered.
The Pearl 2021 is not a small scale, but not overly large either. That said, I don’t like using it directly on an espresso machine drip tray; I leave that task either to an Acaia Lunar scale or a cheap $15 SKG 0.1g scale. I do use the Acaia Pearl’s Portafilter mode frequently when measuring portafilter doses. A handy tip is reversing the silicone heat map so the portafilter handle can sit elevated and more level with the spouts sitting on the main mat area. The Portafilter mode is nice, though I changed the zero-out time for it from 15 to 30 seconds in the scale’s advanced settings.
The Pour over Auto Start mode is probably the most “janky” mode on the device, though Acaia has improved it through firmware updates. In theory, it is supposed to auto-start the timer once it detects water flow into the pour over brewer. It does this almost perfectly. Where problems arise is when the timer auto stops and resets.
A lot of people like to pour part of their pourover brew, then lift the filter to swirl the coffee slurry. If you do so in this mode, the timer stops, and the scale will reset in 20 seconds. The timer stops and the scale resets after 20 seconds of inactivity, but we all know once you’re done pouring water, the brew isn’t done yet in a pour over. The auto reset can be adjusted in settings, including 60 seconds and never, but the timer still stops after it detects the pouring has stopped.
Because of this jankiness, I almost never use this mode, instead opting for the dual display mode and manually starting the timer. I think the solution here is Acaia delivering more advanced setting controls for how the timer works and resets in auto pour over mode.
The scale gets dirty fast (especially the white version) but is also very easy to clean. You can run water over it if you want (top down – never upside down though!) and gently wipe it with a cloth to get spick and span. I regularly put the silicone heat mat in our dishwasher to get it clean.
The scale top will display scratches after a while. The polycarbonate is shiny but seems easily scratched. It’s not a big concern, but it is there, especially if you try to photograph it from certain angles.
The Pearl 2021 has had several firmware upgrades since its launch. These include:
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Improved registering weights in beverage mode.
Noticeable Improvement
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Speed up tar operation and improved tare execution stability.
More Accurate
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Solved issue with screen brightness setting.
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Option to set weight display in dual display to resolution of 1 gram / 0.01 oz.
Acaia from Day 1 has pushed the whole connectivity and apps elements of their scales. Indeed, their display at the 2014 SCAA show with all the iPads showing live Brew Prints was how they got a lot of eyeballs looking their way.
The Pearl has several apps that work with it. Most are available on both iOS and Android, except for the Brewbar App (which is a shame, as it appears to be the most polished app they have, and the only one that seems to work for most users). These include the Brewmaster, Brewbar (iPad only), Acaia Coffee, and Acaia Updater.
Before I dive into what each app is supposed to do, I do have to say the entire app experience right now (except for perhaps the Brewbar, iPad only app which I have not been able to test) is really bad. I could not connect the apps to any Acaia scale I have with my two most recent smartphones: a Google Pixel 7 Pro, and a Samsung S22. If I want to connect or update firmware, I have to dig a 2016 era Google Pixel (original) or old Huawei P10 out of a drawer to get these tasks done.
Even so, getting connectivity is hit and miss, and in some cases, very frustratingly so. An example: after multiple attempts to get the scale I’m using to register and be active with the Acaia Coffee app, and finally getting it to connect, once I start doing a “brew print” recorded brew, the scale will lose connectivity.
Because the app and connectivity is a big part of Acaia scales, the horrid performance of the apps is the main reason why the Pearl 2021 doesn’t have a much higher score in this review.
With that said, let’s get into each app.
Acaia Coffee App
The main app for all Acaia scales is Acaia Coffee. It was planned as not only a data logger and coffee brew diary, but also as an online coffee review community, allowing you to share your “brew prints” (as they call them) with other coffee lovers who use the app and have registered a community account.
When connected to your Acaia scale, it collects brewing data including the coffee bean weight, water weight, the pour time and volume, and displays the scale’s active timers and prompts. You can set up a brewing style for various brewing methods, including when to pause, and how much water volume to pour over a set time.
You can also take pictures of your brews, dictate tasting and coffee notes, put in the coffee’s origin notes, and a lot more information. You can share it all within the built in community. In theory, it’s super feature rich and ambitious.
In practice? To be brutally honest, the Acaia Coffee app has never worked well on Android platforms, and has some very poor reviews in the Google Play Store to back this up. In the last few years, even the iOS reviews are negative. The scale doesn’t seem to connect to apps running on recent flagship smartphones, including the Samsung S21, S22 and S23 series, and Google’s Pixel 7 series.
The app is also horribly out of date in design and ability. It was designed on iOS, and ported over to Android, eschewing all of Android’s native Material Design cues. When you do have it working on a device that can connect to your scale (for instance, I can run connect to the scale using the Acaia Coffee app on a 2016 Google Pixel phone), parts are broken, like exporting your brew prints to images or social media like Instagram.
The Brewmaster App
The Brewmaster App was introduced around the time the Acaia Lunar scale was introduced, giving a more visual, no frills real time readout of flow rates and timings.
The app is a data logger with the ability to add notes, coffee information, and more. It also does the “brew print” view of the pour of your water, like the Acaia Coffee app does. It includes a coffee ratio converter, and it can (according to the iOS description) allow you to share your brewprints with friends, though, like the Acaia Coffee app, this functionality seems broken.
What’s interesting is some of the things promised from the app in the Google Play Store description. Apparently this app was supposed to work with the Sette 270W series grinders. Many don’t know this, but the Sette 270W series have a bluetooth module installed that… doesn’t do anything.
Acaia was also planning on charging, as a paid add on, for a data export feature via .CSV files.
This app also does not connect to the scale on my Pixel 7 Pro phone, but interestingly enough, does connect to the scale on a Huawei P30 Pro (the Acaia Coffee app does not).
Acaia Updater
Acaia also has a dedicated firmware updating app for their scales. I’ll be honest, based on my experiences with Acaia’s other apps, I’m always deathly afraid to use this app when updating the scales and their firmwares. But it’s worked every time I’ve tried it so far, as long as I run it on a legacy smart phone. It won’t connect to my scales from my current phone (the aforementioned Pixel 7 Pro).
Suggestions to Acaia
So it’s established that the entire app experience with Acaia and their scales is… horrible. I have some suggestions for them (and I should note, I’ve given these suggestions privately in the past directly to Acaia’s owner). There’s three directions Acaia can go.
Reboot Everything
If the connected app and live recording experience is important to Acaia, they need to retire all their apps and rebuild everything from scratch, using a competent app developer. They also have to build entirely native for Android as well as iOS. I’d even go the extra step to have similar functionally in both platform apps, but give them the “look” of each platform, individually. Android with their Material Design interface, and iOS with… whatever iOS is these days.
My suggestion is start with the Brewmaster app, but rebrand it as “Brewmaster Lite” or similar. Get all the core scale functionality working bulletproof in that app: data logging, brew print, coffee notes, coffee library, ratio calculations, pour rates, a replayable visual view of the pour (via the pour chart), and more. Have different view modes: a live pour mode that displays only pertinent information in the real time brewing, and a overall brew print mode that displays all the information about each brew after the fact.
Build good output tools: a visual image of the brew print, a larger image showing coffee notes, photos taken etc, and a nicely laid out PDF of the entire brew print. Design the ability to output the live brew mode as a .mp4 video file.
Once that’s done, build the Brewmaster Pro app. It would use Brewmaster Lite as its core, but incorporate Acaia’s community features, advanced sharing beyond the stuff found in the lite version, and exportable data logging. Charge money for it. Maintain and update both apps regularly.
Go for the Basics
The second option is, retire all current apps, sunset the community features, and just build a rock solid data logging and brew print app that has quality share features. Have a regular version, and a “pro” version for roasters and such that have exportable data logging information.
Interestingly enough, there is an app out there that actually works with some Acaia scales and is very highly reviewed: the Bean Conqueror App. It would be really smart for Acaia to just hire this fellow to build an entirely new official app for their scales. This could be Acaia’s new “basic”.
Give Up
The third option is, just give up on the whole connected app thing. Have a basic app for updating firmware that actually works on current smartphones, and call it a day.
Some 4,000 words ago, I mentioned we don’t have a test protocol for scales. But we do have a lot of scales here at CoffeeGeek, many of them designed specifically for coffee. There’s the Hario scale, the Timemore Black Mirror Scale, the Brewista Smart Scale II, just to name three.
ed.note 2024: Timemore’s scale is not recommended any longer, and they’ve discontinued it, replacing it with a new generation model which we have not tested. Scales comparable today are the DiFluid Microbalance Ti, and the 3Bomber Mini Scale II.
Timemore Black Mirror
The Timemore Black Mirror scale is maybe the closest to the Pearl in terms of app functionality and offerings. It has its own version of the “Brew Print” and while it doesn’t have a visual flow indicator built into the scale, it will beep at you if the scale detects you’re pouring water too fast. The Timemore app is also quite janky and temperamental. When it comes to accuracy, the Timemore cannot approach the accuracy and precision of the Pearl’s innards; that said, it works as well as any $50-$75 scale out there.
The Timemore has a bigger battery than the Pearl 2021 (1500mAh vs. 1100mAh), but only has about 10 hours of run time, so I can’t quite figure out that disparity. Its registering of weights in real time is noticeably slower than the Pearl, especially in espresso pours, and the boot up time is a bit longer. It does not have the Pearl’s resolution through its weight range, switching to 0.5g at 500g, and 1g at 1000g.
The Timemore Black Mirror does not have any of the advanced programming ability the Pearl does. For instance, it has a default 3 minute auto-off that cannot be modified.
Brewista Smart Scale II
The Brewista Smart Scale II is, in its own way, an interesting and nice scale to have, but it feels like previous-century technology next to the Pearl scale. That said, it does have a variety of programmed brewing modes, from full manual to auto tare and timer modes, to pour over mode. There’s no app, no bluetooth; everything is inside the scale in terms of functionality, accessible through one or more of its four buttons.
The best things about the Brewista scale are its size and screen readability. The buttons are very small and sometimes easy to miss. It does fit right on your espresso drip machines and the included silicone over-mat makes it more water resistant and heat proof.
The scale cannot keep up with the Pearl’s accuracy, real time readouts, or battery life longevity.
VS Other Acaia Scales
The Pearl 2021 scale is the fastest Acaia scale I currently have. By major differences in some cases. That said, I do not have the most recent Lunar or Pearl S scales, so I cannot compare to those.
I have used the Pearl 2021 scale next to the Acaia Pearl S scale quite a bit, and while they are very similar in a lot of their functionality, one particularly annoying thing about the Pearl S is that it takes 3.5 seconds to boot up; the Pearl 2021 is under a second. The Pearl S also seems slower in registering changes to weights.
The Pearl 2021 scale is noticeably faster than the Acaia Lunar scale, though the Lunar has some of the Pearl 2021 features like the icons for modes. The Lunar also has six brewing modes, with 3 of them focused on espresso brewing. It can also read and display down to 0.01g resolution if you change an advanced setting. And unlike the Pearl, you can set pre-infusion modes on the Lunar for espresso brewing. The Lunar’s battery is smaller and charges via Micro-USB, which is old technology now.
All the improvements Acaia has touted in the Pearl 2021 vs the older Pearl scale are evident. It is faster to boot up. Faster to read and adjust. Brighter to look at. Longer lasting in the battery. More user friendly with the iconographs instead of yellow and green lights. Faster to charge. 0.1g readout in timer modes. But the visual flow rate indicator and the Beverage modes are the real standouts.
(ed.note 2024: we now have more modern scales, and will compare the Acaia Pearl 2021 model to these in their respective reviews; key and eye out of the DiFluid Microbalance Ti especially, which really matches the Pearl in some regards, and beats it in others (like app ability).
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Acaia took the industry-leading, standards-setting scale of the specialty coffee world – the Pearl Scale – and improved it in almost every way with the Pearl 2021 model.
The standout, killer feature for me is the visual flow rate indicator. It literally has made my pour over coffee better. I thought I had a handle on my flow rate and control when making pour over coffee, and the Pearl 2021, with it’s real time ability, showed I still had work to do.
The improved beverage mode has become an indispensable tool for our evaluations of coffees here at CoffeeGeek, and it has also provided a tool to our arsenal of testing equipment when evaluating pour over coffee makers. For the typical home coffee lover, it will help you with the consistency of your pour over coffee, and provides you with digital results that normally would take a lot of note taking and calculations to get.
If you own an original Pearl, the Pearl 2021 is a worthy upgrade. The visual flow rate and improved beverage modes are worth it. The good news is, Pearl scales have good resale values, so you should be able to sell it on Facebook Marketplace or Craigslist and recoup a good portion of the new Pearl 2021’s cost.
If you own a budget scale and do a lot of pour over coffee, the Pearl 2021 scale is a purchase you might consider for its ability to improve your brews and teach you more about the process and achieving consistency. At $150, it is steep and will probably be the most expensive thing in your pour over kit (except for the grinder); it’s not for everyone but it is a worthy tool.
If you have invested a lot in your home coffee setup, including a quality grinder, a capable espresso machine, a pour over setup, and other brewers like siphons, press pots etc, the Pearl will be a near perfect addition to your gear.
The true downer for this scale is the app experience, and the extremely flakey connectivity issues. I’m literally afraid to update the firmware, it is that bad on Android. This scale should be scoring 95 points overall on our rating scale but it charts in at 89 points, barely making Best in Class, because of this.
Still, this should not prevent you from buying this scale. That’s because the Pearl 2021 is the best general purpose coffee scale you can buy today, and is CoffeeGeek’s highest rated and recommended scale.
The Acaia Pearl Scale is $150USD and is available from some of our CoffeeGeek supporters, including Whole Latte Love ($150USD).
Please note – this is not an affiliate link. In fact, these vendors will have no clue what directed you to them if you click these links and buy from them. So, if you found this review helpful, please consider buying from these sources and tell them where you found them. It will help our website. a lot!
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9.0DesignTo be honest, the design’s a bit dated now, but was innovative when it came out, so still scores high.
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8.5UsabilityNo tactile feedback (haptic mode would be awesome), plus occasional missed button presses. Advanced menu a bit tricky to use.
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8.5FeaturesExtremely feature rich scale, but the broken app experience takes some expected features away for many.
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10PerformanceFastest and most accurate scale on the market. Instant feedback is a boon.
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8.5Value vs. CostIf the app experience was on point, this would be 10/10. Still, you get a lot for your $150.
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9.0Quality of BuildExcellent build quality throughout, water resistance a nice bonus.
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8.5Service / WarrantyThey do answer emails quick, and do some firmware upgrades. But they need to overhual the apps.
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9.0Included in the BoxUSB-C cable, well packed and protected, overall good.
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9.5Resale ValueWe’ve seen these scale go for as much as 80% or higher of original value when sold used.
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8.5OverallPoor app experience offset by this scale’s industry leading ability.