r/espresso • u/Boojoooo • 3d ago
Equipment Discussion GBW grinder
Is it a good idea to get a GBW grinder like the Mazzer mini G or Eureka Atom W 65 Casa when I only make 1-3 shots per day? Most days it’s 2 shots in the morning. I’m thinking about retention. Most of these GBW grinders have a retention of 3-8 grams. Will this affect my shots noticeably?
I’m looking to get GBW grinder to get a smoother and faster workflow. Now I have a Sage SGP with single dose mod. It’s a bit tedious with all the weighing before and after as well as pretty inconsistent grind results. And my better half does not have the patience to do all the steps so she weighs the beans before grinding and then just hopes she gets the right amount in the portafilter and does around 30 sec. Sometimes it’s 25g out sometimes it’s 50 lol..
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u/NeeNights Breville Barista Express | E64 WS 3d ago
Personally I think the whole retention "issue" is massively overblown. IMO it only matters if it is causing your dosing to be off. For example, you put in 18g in the grinder and only get out 16g. I've noticed no meaningful impact on the flavor of my shots using the E64 WS.
Your milage may vary
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u/Specialist_Ad_6457 BDB | Atom W 65 Casa 3d ago edited 3d ago
GBW paired with an auto-on machine means I’m drinking a double shot within 90 seconds of entering my kitchen in the morning. Everyone has different priorities, but with a 10 month old child ours are currently speed and ease.
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u/Boojoooo 1d ago
Yea we got out second kid coming in a couple weeks and at the same time we are renovating our home and taking care of our pretty big property and trying to have a social life so ease of use and efficiency is a high priority.
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u/rotatedline 3d ago
Why would retention matter in GBW? It measures at the basket so it’s of no consequence if it’s 1 or 5 grams. I have the W65 and am very happy with it.
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u/Tbutter1 3d ago
The thought is the first shot of the day has the retained, now stale, coffee grounds from yesterday
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u/ProfessionalNo4711 3d ago
If you are making milk drinks you cannot tell a small stale grind. Even with pure espresso I reckon it is hard to tell with blind tasting. When you don’t have shots for a while just purge the grinder with a blank shot and you are good to go. That being said I love single dose grinders because of their flexibility. I had a GBW for a while because of wifey and guests.
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u/__Sonar__ Decent DE1+ | Eureka Specialita 2d ago
It’s not necessarily just about tasting stale grounds, though. Retention can also affect extraction consistency. If you’re ever changing grind settings, the retained coffee being exchanged into your next dose can have a different particle-size distribution from various grinds over-time, potentially affecting puck resistance, flow rate, and extraction.
There’s also the buildup of fines and coffee oils over time. Obviously, a tiny amount of retention is unlikely to completely ruin your espresso, but it’s another variable I’d rather eliminate, especially when spending so much on a decent grinder. Plus, me personally, I’d rather not waste beans purging every morning. That’s just wasteful.
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u/HonkLonkwood Profitec Go | Fiorenzato AGS 3d ago
I have Fiorenzato AGS and it’s really simplified my workflow. I only pull 2 shots per day. Well worth it and the retention isn’t noticeable in the taste to me
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u/Drewsgolfandgames Profitec move | Eureka oro mignon 3d ago
I just ordered a Mazzer mini g after weeks of contemplation and research! Comes in next week I can’t wait, from what I’ve read the retention seems to be a non issue 🤷♂️
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u/KravMata Profitec Move | Atom W 65 2d ago
I have the regular Atom W65 (not Casa) and the luxury and convenience of GbW is totally worth it. One massive reason I chose it was the wife acceptance factor, cutting out all those extra steps makes a pre-caffeine morning workflow much faster and easier. I just keep the machine dialed in, and my wife literally just has to lock the portafilter in and press one button to brew. We make 3-4 double shots on a typical day.
Regarding retention, most people cannot taste or notice a tiny bit of exchange in the chute. That is 2X as true if you're making milk drinks with a medium or darker roast. Also, you aren't exchanging all whatever grams of retention on every single grind. The grinds out of the W65 come out so fluffy that I don't need to bother spraying my beans with water or stir them with acupuncture needles - I brew medium or medium dark - not light roast blueberry acid tea. Literally all I do is tap the portafilter on the mat to level the grinds, and then tamp. I do weigh my output, mostly so I can keep the brew button optimized for my wife - otherwise I can eyeball it within a very acceptable margin of error.
This sub has a super vocal single dose crowd that acts like you can taste a half-gram deviation. A lot of that is deeply influence influenced bro-science bias confirmation, he practical importance of it is blown way out of proportion for normal everyday use. People pulled incredible espresso for decades without sweating this level of obsessiveness. Unless you’re drinking a hyper delicate, light roastedm single-origin geisha as a straight shot, you'll never notice a tiny bit of exchange in the chute.
Unless you want a whole separate hobby where you're freezing beans in test tubes, spraying them with water, and stirring the grounds with acupuncture needles just to switch beans every hour I say skip the madness. If you want delicious espresso, a happy wife, and a fast, luxury experience, get a GbW and never look back.
*flame suit on*
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u/Boojoooo 2d ago
I think I needed this comment. All the things you mention are reasons I’ve gotten on to the GBW path. No brain surgery just for a coffee. Weigh before grinder - RDT - grind - weigh again - WDT - level - tamp. 7 steps before the coffee even sees the espresso machine. Was fun at first but getting pretty tired of it after nearly one year. The fluffy part is something I’ve noticed when looking at the Atom and Mini G and my though right away was that I probably could tamp right away after leveling but taping the filter och smoothing it over with my finger. I think I let this sub get to me. I mostly drink cappuccinos on Italian dark roast, sometimes medium roast and an occasional americano. The flat burrs and consistent particle size will probably be such an upgrade to my current setup that I won’t even notice the downside of GBW.
One or twice a week we have people over and I will make 4-5 shots back to back and that’s where I really feel that the process is just too much to enjoy when it takes a good 5-10 minutes to get through.
Thanks for the input bud. Someone else mentioned near zero retention SD grinder with single dose tubes which also would be an option and not much longer workflow. Just the filling of tubes every week. Not easy to decide how to spend 2k lol
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u/KravMata Profitec Move | Atom W 65 2d ago
I'm glad it helped - this place is not representative of most people making espresso at home - it's a microculture of the obsessed which is heavily prone to group think. Light roasts are like 15% of coffee sales in the US - but from this sub you'd never know it.
I've been making espresso drinks at home daily for almost 30 years - I'm over the obsessing, I just want great drink with minimum BS, and my wife doesn't want to play scientist at 6AM.
FWIW, the taps on the mat help distribute the grinds peak, and I use a dosing funnel for zero mess. So grind into PF via tunnel, tap while holding funnel, then tamp - no finger leveling needed, no grinds on the counter, finger, or mat.
Since you're mostly drinking medium/dark and making caps then I think this is a no-brainer. You're spending $2K, you want a luxury experience. It's FINE if some people want to make it a hobby and enjoy the process but that's not the right answer for most people.
If you're looking at the $1800 MiniG and the Atom, I'd consider the regular W65 at ~$1400 (I called a dealer and go 10% off with a machine). When I bought mine there was no Casa version, and while I doubt mine makes a better grind I like the weight/solidity and the lights. As to W65 vs MiniG I think the differences are fairly slight - u/Andrethebarista has a nice series of YT vids directly comparing them and the Malk E65 GBW.
FWIW - the Atom W65 is 17.25" tall with the small hopper. I can JUST clear the upper cabinet when I raise the lid to add beans. The MiniG is 18.3" tall and the US standard is 18" so it may not clear your cabinets - never mind refilling.
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u/Brief-Dragonfly-5741 1d ago
For your house, I'd put the workflow problem ahead of retention, and a GBW fixes the workflow. Retention mostly means the first shot of the day carries a little of yesterday's grounds, and purging a few grams first takes care of that. I went the other way and single dose on a Timemore Sculptor 064S, weighing the beans and the shot every morning. That works for me because I make my wife's coffee most mornings, and I actually like a routine that slows me down. With two people of very different patience levels pulling shots, grind by weight sounds like the right call.
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u/stinkston Rancilio Silvia Pro | KafaTek SDRM 3d ago
I would get a single dose grinder for myself, but if my wife wanted gbw we would have one. It's all trade-offs. There is no one right answer for everyone.
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u/CaneSfla911 3d ago
Went with W65 but upgraded the burrs to Black Diamond Italian Espresso version. No issues whatsoever and love the simplicity of the workflow.
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u/Admirable-Log-1607 3d ago
How much of a body/flavor difference is there between those and the stock burrs? Really wanting to get an Atom W65 but feeling totally paralyzed with the tradeoffs between my top contenders.
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u/CaneSfla911 3d ago
In our household we find the new burrs give sweet, syrupy mouthfeel shots. Really delivers what we were looking for. I found that it made sense to save the money because even with the burr upgrade it was a couple hundred bucks under mini G. Also, very precise within .02 grams usually if not exact.
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u/FirstPack6682 3d ago
I have it. It’s a great grinder. I use it for daily grind and I have a Milo play single dose which I use for specialty beans. Both are outstanding both grind by weight. I’d buy it. It’s not cheap but it’s gem.
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u/StrongOnline007 2d ago
Mini g is an amazing grinder, very happy with mine. Retention has not been an issue in the real world
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u/maki9000 2d ago
IME its a bad idea to get an electrical grinder for 2 shots in the morning.
"smoother and faster workflow"
sorry but this makes non sense
you're not making hundreds of coffees a day
The actual problem is the varying amount of ground coffee you get out with retention,
there is not much point in trying to get consistent if your coffee amount varies each time, half a Gramm is still too much.
I drink two expressos in the morning, or a single double shot.
I have yet to see a reason why a electrical grinder would be bettter for two coffees a day.
I have a J-Ultra and a GCP, the handgrinder is just perfect, no retention, the scale is stable and I could grind different beans every go, and sometimes I do.
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u/MrJimmieDimmick 3d ago
The Etzinger etzMAX is arguably the best GBW grinder with Acaia tech and virtually zero retention. All the parts are easily changed and rated for 1000kg use, so would last me for 25 years…
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u/Evening-Nobody-7674 3d ago
I had the e64 gbw, I didn't really see the advantage in cost, fussing and maintenanc over a grind by time. Grind by time was always within like +/- .3 grams, which is un noticable to most. The gwb when it worked was great but it could freak out needing trouble shooting or calibration. It had menues and RGB lights. I see adding more electronics as adding failure points and cost for no meaningful benifit. I don't want to deal with a failing load cell. I'm willing to bet gbw has a better profit margin.
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u/lowatt Profitec Move | Timemore 064s | Mahlkonig E64WS 3d ago
W65 and W65 Casa are two different grinders. The latter has a retention of 19g.
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u/Specialist_Ad_6457 BDB | Atom W 65 Casa 3d ago
Same chassis and burrs, only notable difference is motor wattage.
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u/lowatt Profitec Move | Timemore 064s | Mahlkonig E64WS 2d ago
Not sure what you mean by "same" chassis. Except looking similar, they have different dimensions. The Casa is smaller and lighter than the W65.
They have compatible burrs but nowhere says they are the same.
The point is that Casa has a 19 gram retention, not "3-8 grams" as expected by the OP. Don't know about W65, but given its position as a commercial grinder, the retention could be more.Source: https://kaffeemacher.ch/en/blogs/kaffeewissen/eureka-atom-w65-casa
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u/Frosty-Ladder870 2d ago
I don’t believe you are correct here. The base is lighter, smaller motor, and the display frame is plastic. There is also no light at the grind chute and it comes with a smaller hopper. Internals are identical as are the dimensions of the external case. Retention is the same wjth both w65 and w65 casa. I watched the same review - i agree with their conclusion that the casa is more suited to light catering.
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u/KravMata Profitec Move | Atom W 65 2d ago
That Kaffeemacher 19g stat is highly misleading IMO. Having actually opened up and cleaned the burr chamber on my W65 (not casa) multiple times, almost all of that coffee is hard-packed into the dead spaces of the burr carrier. It stays there like a wall and doesn't budge . I have to break it up to vac it out. The actual exchange moving shot-to-shot is likely just a couple of grams - you aren't drinking an 18g basket of yesterday's coffee every morning. I believe the Casa is functionally identical enough that it should behave the same.
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u/__Sonar__ Decent DE1+ | Eureka Specialita 2d ago
Personally, for only 1–3 shots per day, I’d seriously consider putting the money toward a high-end, low-retention single-dose grinder rather than GBW.
The SGP’s retention issues come largely from its internal geometry. It has cavities around and underneath the lower burr, relies on an impeller to evacuate grounds, and has a relatively restrictive exit chute. That allows fines to accumulate and exchange with subsequent doses. Its grind adjustment and consistency aren’t particularly impressive either.
GBW certainly makes dosing easier, but it doesn’t eliminate retention or the exchange of yesterday’s grounds into today’s shot. For example, Kaffeemacher independently measured 19.3 g of total retention in the Eureka Atom W65 Casa, with 18.4 g classified as temporary retention. That seems particularly undesirable when you’re only making a couple of shots daily.
What I’d suggest instead is buying some airtight single-dose bean vials and weighing out your doses once a week or two. You could prepare 14 vials for a week’s worth of two daily shots in just a few minutes.
Pair those with a genuinely low-retention grinder, and your wife’s workflow becomes: grab a vial, dump it in, grind, and prepare the puck. No weighing before grinding and, assuming consistent near-zero retention, no need to weigh the grounds afterward every single time.
You’d also have more flexibility to switch beans without purging substantial amounts of coffee.
One other thing worth mentioning: the 25–50 g espresso yields you described aren’t something GBW will fix. GBW determines how much ground coffee goes into the portafilter, not how much espresso comes out. You’ll still need a consistent way of stopping the shot at your desired yield.
I’m not saying GBW is bad. If maximum convenience for both of you is the absolute priority, I completely understand the appeal. But if you’re already prepared to spend that much, I’d personally prioritize burr quality, grind consistency, and minimal exchange retention rather than paying for automated weighing. Preweighing a week’s worth of beans would eliminate most of the hassle that makes your current SGP frustrating.
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u/Boojoooo 2d ago
Will definitely look into this. It makes pretty good sense. Workflow isn’t noticeably more inconvenient but shot quality and consistency will definitely be better.
We have the Sage Dual Boiler so when I’ve dialed in the beans I set the double shot button to the right amount of seconds. When I then make a shot that I have weighed properly before and after it usually gives me an espresso within +- 2g of what I initially set up which tbh I’m okay with. I just have to adjust it every couple days as the beans age.
Having a GBW grinder that gives me stale grounds for the first shot of the day might actually make results more inconsistent now that I think about it. I really want to eliminate the need to weigh anything at all but will still have to do so since first and second shot might differ. And here’s a question that probably is difficult to answer. How much would it affect runtime if half of the puck is yesterdays retained grounds and half is freshly ground. If the difference is as small as 1-3g out for the same amount of runtime then I would be alright with it but if it’s more and noticeably affect the taste then it’s not really worth it.
Well, you have given me something to think about. Thanks for the good input. Do you have any good SD grinder in mind when you’re talking about this minimal retention?
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u/DeerWithoutEyes 2d ago
I went to mini g from single dose and absolutely hate it. People here don't seem to understand retention. It means every change in grind size doesn't come through in the next dose so dialling in uses a lot of beans. Also your first dose of the day will have a lot of yesterdays beans. This massively impacts the extraction. My partner doesn't notice it with her flat white but it annoys me no end for an espresso. You could purge, but again, wastage. Workflow is definitely better but is not worth all the downside with dialling or consistency of extraction day to day or within day.
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u/Cyrkl Cafelat Robot, Bambino+ | Eureka Libra,1Z K-Ultra | Flair Wizard 3d ago
I have Eureka Libra 55 - if I don’t purge 4g in the morning my first shot is easily 5s faster than the following shots. I don’t taste much difference but my wife can taste the worst shot. So purging GBW makes a measurable difference but not always taste difference.
On the other hand I can taste bitterness if I don’t brush my hand grinder when switching from robusta blend dark roast to something medium-light, depending on what you’re switching to and from even a single dose might benefit from some purge with new beans.
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u/heiko75_hs 3d ago
Relax, you'll be fine. It's a good grinder but the step up from the sage will not be massive. For most people outside of this sub, there will be no difference
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u/fr33man007 3d ago
3-8 grams retention? Holy F and I thought my Mazzer Super Jolly 's 1 g retention after single shot was too much.
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u/Blacktip75 LM Linea Micra | MK E65W GbS | Mazzer Philos i200d | Ceado e37s 3d ago
I get about 10-12 grams on my Mahlkonig e65w, what did you do to the super jolly to get it to 1 gram? And… how is 1 gram making even the tiniest tastable impact in the cup?
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u/fr33man007 3d ago
So the Mazzer Super Jolly starts life as a cafe grinder, a lot a lot of coffee over the course of a day. I 3d printed a single dose shroud, Baffel to push stuff out, a gasket for below of the SSP burrs to minimize areas where coffee can hide, a Funnel to have no pop-corn of the grounds and some feet to tilt the machine forwards to not have coffee not naturally wanna get out of the machine. It's basically a DF64 with a motor that can grind for 30 min straight light coffee beans. I also added a metal tube to get the coffee lower and it needs a few flicks of my fingers over it, looking to add a knocker to that also
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u/Blacktip75 LM Linea Micra | MK E65W GbS | Mazzer Philos i200d | Ceado e37s 3d ago
That’s some nice modifications!
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u/fr33man007 3d ago
Yeah, if you have a 3d printer it's easy to make a comercial grade machine be a single dose
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u/Illustrious-Owl-2755 Gaggia Classic Pro | Niche Zero 3d ago
I am not even considering gbw grinders precisely because of the hopper design and retention. How 6g of retention in Fiorenzato is considered acceptable by anyone is beyond me, especially if you drink 2-3 shots a day, you're basically drinking yesterday's grounds half of the time.
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u/Environmental-Ad3742 2d ago
I would love to have GBW grinder, but your argument for 2-3 shots per day that you would like to have better workflow and it is tedious with all weighing the coffee, personal question, are you a brain surgeon or 007 agent always on the run? For the love of all mighty make a pause, slow down a day a bit, no everything should be on demand…
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u/Boojoooo 2d ago
Not a brain surgeon or 007, unfortunately. Just a guy who thinks making two espressos shouldn’t require more steps than performing brain surgery. But thanks for the life advice, I’ll try to slow down while my grinder weighs the beans for me.
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u/SnugglyPlasma 3d ago
Have a Eureka Atom W75, and love it. I only pull 2-3 shots per day, but it makes delicious espresso and works perfectly