Hario MSS-1B Mini Mill Slim Coffee Grinder

After a few months of searching around for the right grinder, I finally settled on the Hario Slim Grinder. I do a bit of home brewing during my down-time and I use a range of equipment: an espresso machine, Hario pour over, an Aero-press, and occasionally a siphon. Let’s just say, I have a wide range of daily coffee needs but I was not willing to shell out big bucks for a super high end grinder. Why? Because I am not a pro, it wouldn’t have been practical and I don’t have a shop sitting downstairs in my kitchen, just a personal coffee lab. I had a short list of requirements for my new grinder:

  • Conical Burr
  • Able to do espresso for commercial machinery
  • Inexpensive for the quality
  • Portable-ish
  • Easy to adjust precisely


Enter the Hario Mini Mill Slim Grinder. Hario has always been a go-to company for many baristas because their equipment is efficient, dependable, durable, well designed, and practical. I am a big fan, but secretly because it is a Japanese company. The number of shops that use their top of the line equipment is a testament to how well designed and manufactured Hario products are. After reading some reviews and testing one out, I picked up the Slim from a shop downtown for a little under $30. I immediately ran over to my shop, clocked in early, dropped it in a PuroCaff bath and went to work. A quick word to those who are looking into buying one: search around for the best price, I have seen these things go for as low as $25 and as high as $50.

The best way to describe the Slim is quality; it is really straight forward and simple. It features a ceramic conical burr that is extremely precise and easy to adjust. The adjustment mechanism allows you to “click” between settings for fine espresso or much coarser drip coffees. The ceramic is also good because, both due to the low RPMs of hand cranking and the material, it will not heat up or “roast” fresh grounds. This tends to be a problem even with higher end electric grinders; you sacrifice some quality for precision and speed with metal burrs because they spin at very high RPMs and generate heat. I also don’t have to worry about my burrs rusting and cleaning it is really easy.

The Slim is a tank; I carry it around in my bag between home and work and there has been no damage or even scratching. Last night I wanted my roommate to feel what its like to use a nice hand grinder. After some confusion, we ended up unintentionally taking apart the Slim and smashed the body and beans on the linoleum. Not suprised, the Slim was fine. The handle is also an excellent length for proper torque, big but not so much to be cumbersome.

I also love how portable it is. The larger Hario Skerton grinders is a bigger and while it may be better in terms of volume and features, for what I do, I can’t imagine needing to grind more then I do with the Slim. For those who plan to feed more than few people with coffee or someone who has a more permanent home for their equipment, consider the bigger Skertons. If I need to pull a shot, I grind the beans super fresh and only fill up about a third to half the space of my grinder. Even when I am making siphon coffee for the house (four people), I can easily make enough coffee with my grinder. It is also cheaper and small enough to travel easily in my coffee bag or messenger.

I want to take a minute to talk about the precision of the Slim grinder. I bought the Slim under the presumption that it could produce espresso fine-grade grinds. Even though my home machine has relatively low bars of pressure and is, suffice to say, weak in comparison to commercial machines, I hoped this Hario piece could exceed my needs. To test out its capabilities, I decided to use it to grind for the Mistral at work. If it worked on that centerpiece, it would work on anything. I played with the settings and buffoonish tried to make espresso grinds on the “3 or 4 clicks open” setting. Way too coarse; my espresso shot out like water. Then, I tried the “one click open” setting.  The grounds were so fine and powdery, unbelieveably even and cool to the touch. I put the new dose in the machine and waited. Sure enough, after about 8 seconds of pre-infusion, the espresso came out as thick and beautiful as doses from the Mazzers. I couldn’t believe how well the Slim worked with the highest end machine! Running on a “craftsman’s success high” I tried it out on the rest of our equipment. Adjusting other settings was simple; about 5 to 7 clicks for drip, 10 for my Clover, and 8 for the siphon at home. Open the container, click the knob, and you are ready to use this grinder on whatever machine you need. Solid.DSC02495DSC02498

The most important aspect for me has nothing to do with tech, freshness, value or efficiency; I just like grinding my beans by hand. Using this grinder just feels great. Not only is it easy to manipulate and smooth to operate, the entire cycle of dosing, adjusting, and finally grinding away feels meditative, allowing me to slow down, reflect and enjoy the brewing process. I can watch my breakfast cook or boil water while I lean on my counter on a sunny morning and methodically just turn, turn, turn. Watching the grinds fall down is like watching a sand timer, elegant and anticipating. The smell of freshly ground beans is intoxicating. If for any reason you choose to fresh grind your beans, it should be just to enjoy that amazing aroma. When you do it by hand, you know you are utilizing your beans to their peak quality, they’re fresh, equally ground, and the fruits of your handiwork. I am a coffee nerd, word and yes, I think it’s “just fun” to grind beans. It really is a satisfying experience and maybe of my favorite parts of brewing at home. With the Slim, I can do it anywhere and anytime and know that I will get the same high quality consistency every time.


Geekyness aside, some people don’t understand why I have one of these. After I bought my brother a siphon and a pound of high end coffee to satiate his “science nerd” needs,  he came to me and admitted that he didn’t own a grinder… two months after christmas. I hastily directed him to Hario, but he had already gone ahead and bought a Bodum. Not a bad choice, my roommates have one and it does the job for FP. But I want a lot of control and and precision in my grinder, plus I want to feel like a “cool barista.”


One morning, I woke up and decided to make my brother and his friends some coffee before they left for work. When I was a kid, I always loved the Foldgers commercials because everyone looked like they were having a blast getting up at the ass crack of dawn, opening up the “ark” of a coffee container to a waft of coffee goodness, and making a fresh cup of coffee. This morning was literally like a Foldgers commercial minus the s***iness of their coffee. I set up my equipment in the kitchen, sun beaming through the windows, put fresh beans in my Hario, and slowly ground them while watching my eggs sizzle. My buddy came in with a look of surprise, looked at me, then my hario, then me again. Then he asks a pretty reasonable question,

“What are you doing?”

“Making you coffee”

“No I mean, why are you grinding it by hand?”

“Because it’s fun, I like how hand grinding feels”

“Doesn’t John have the electric one?”

“Yeah, but it isn’t precise enough for what I want to use it for”

“Oh, ok. But isn’t that hard?”

“No, it’s fun”

“You really must love coffee or something.”


Yes, yes I do. For me, everything during that morning process came together in such a comforting way: I could easily adjust my grind, fill it with the beans I wanted, grind at my pace, and smell the delicious aromas escaping the container before putting it in the siphon. Good point though, to someone who isn’t concerned with “coffee jargon” the Hario doesn’t seem all that practical. Fair enough, maybe this isn’t for every consumer. But for those of us with passion, yeah, go for it, it is well worth the money.


The Slim does have a few draw backs. Because the container is so easy to take apart and adjust, it is also easy for the handle to come off while grinding. There is a certain figure-8 rhythm and way of holding the Slim that reduces this problem, but it can still fall off from time to time. They could have affixed the handle to the cover, but then it would not be nearly as compact. Hario is a glassware company, but the Slim container is plastic (though hearty). Some people have said this makes it look and feel cheap, but I actually like it. I orignally used to rest the container on the counter while I ground. Sometimes, the whole thing would slip and fall down. If it had been made of glass, it definitely would have shattered. Since this isn’t a brewing device, I think I can live with plastic. I cannot, however, live with the smell. Something that scared me away from the Slim were the negative reviews about the plastic “toxic” smell that came out when you first opened it. Some people succeeded in ridding their Slim of the fumes, others said they couldn’t. I had a difficult time getting rid of the smell. I put it in a Purocaff bath, ran boiling water through it, let it sit over night in soap, ran it through the wash, and yet the smell remained.  The worst part was the odor permeated into the fresh coffee to some degree. That was a huge issue. Then, someone suggested I just air it out after each use. I instinctively kept it assembled and closed most of the time. Sure enough, leaving the grinder disassembled for about an hour got rid of 99% of the smell. It came back once, but letting it air generally solves the problem. Oh ya, and one more thing, I have seen a lot of people ignorantly mocking the Hario company and their equipment because they cannot understand the instructions (despite the pictures) because they are “in some kind of Chinese dialect or another Asian language.” It’s in Japanese, Hario is a well established and highly accredited company, not Chinese, you ignorant ****s. If you cannot figure it out on your own, don’t touch espresso machinery.


Overall I love this grinder because its simple, easy to use, precise, portable, professional, and well built. I have seen many good baristas with one of these at home and I would suggest it to anyone in a home setting because its a great value. I plan to use it at my coffee lab on Mondays to offer single origin espresso as an alternative to our blend. Thanks for the great equipment, Hario!


14 Comments Add yours

  1. Sedi says:

    Hi there!

    Loved ur article on the Hario!Just wanted to ask the life length of the Hario hand mill. I’ve heard the burrs get worn out within a year. Is that a fact?



    1. Dear Sedi,

      Thanks for visiting the website! Much appreciated. So, I have had my Hario for a little less than a year now. Before I got my electric burr grinder, this was my go to. Now, I generally just use it when I am on travel or when I want to bring a “mobile coffee lab” to a friend’s house. So far, no problems with the burr as far as I can tell. I can say they do feel quite delicate, but I have put some extremely unroasted beans in the burrs and did a little grinding without a problem (though they probably would have broken the burrs had I done much more!). So, unfortunately, I cannot give you a definite answer. I also regularly put rice through my burrs to clean the coffee out and keep the blades in good condition.




      1. Arnaud says:

        Dear James,

        Just like you, I enjoymy MiniMill but I encounter a problem when making coffee for my Cona syphon machine. I ust explain that I am keen on using a glass drainer instead of a filter. Unfortunetaly it tends to clog.
        What is strange is that using pre grinded coffee from the supermaket is not making any problem.
        I have tried various settings. it seems like 7 or 8 clicks are the best but it works very seldomly!

        would apreciate if you could help!


  2. Wow. This review was a pure pleasure to read. I love your passion for the craft and I read the sentence about “slowing down and enjoy the brewing process” several times. This review made me happy and I can relate to your passion for coffee and i just ordered this grinder. Thank you, I’m so gratefull:)


    1. Dear Hallvar,

      Really glad you enjoyed the read! I do my best to let my passion come through with the writing. Also glad you ordered the grinder, I am a big advocate of Hario. I took mine camping last week and it is still working out great for me.


  3. Alex says:

    Thank you for your great review! I’m about to order this grinder on the German Amazon, I tried to find a reseller here in the Netherlands but there aren’t which is a big shame. Keep up the good work!


    1. Alex,

      Thank you! It is a great grinder. Lately i have been taking a few filters, a small pour over cone, and this grinder with me to friends houses and serving up some brew. enjoy!


  4. Jerome Prieur says:

    Hi I thoroughly enjoyed reading this review and I have a follow up question. I have athe hario burr grinder and I’m trying to find the right setting (number of clicks) to use it with my espresso machine (a pretty basic delonghi – I am a beginner in the art of coffee making). I found that if I only use 1 click the coffee is so fine that the water won’t even “go through”. Eventually, after several minutes the coffee drips out of the machine very slowly. On the other hand, if I use a 5 or 6 clicks settings then it comes out watery.
    Maybe there is something else I’m doing wrong (the tappering of the coffee powder in the percolator maybe?) that ends up making the coffee too compact, or something else.
    I was hoping that maybe you could share some basic advice on that issue with me (and the rest of the web).



    1. Jerome,

      First of all, thank you very much for taking the time to read the article!

      I too had similar trouble perfecting espresso with this thing. I tested it on both my shop’s Mistral and Cyncra, and the 1 setting worked perfect in those. However, on my little home Mr. Coffee machine (which is not a good machine by any means but can get the job done if you tweak it), I had to put it on about 3 clicks past 0. It’s a delicate balance, but I find that if you use a legitimate tamper and apply 30 lbs of pressure on that setting, it works decently. The coffee should be compacted enough so it wont fall out and stays firmly in the portafilter, but don’t over do it since many home machines just are not powerful enough to put water through “finely ground” (and appropriately ground) espresso. It is just a limitation of home machinery, it will never be perfect. Hope this helps! I might try to mess around with mine to see if I can get any better answers for you.


  5. Mal says:

    Great review! I’ve just started using the Mini Mill and can’t recommend it enough. And I totally get the meditative side of making coffee with this; love it.

    I was wondering – how often would you suggest cleaning the Mini? After each use, once a week? The instructions say that taking it apart and soaking the parts in diluted dishwashing liquid works, but doing that after every use would be a bit much.

    Thanks in advance!


  6. Mal says:

    Great review! I’ve just started using the Mini Mill and can’t recommend it enough. And I totally get the meditative side of making coffee with this; love it.

    I was wondering – how often would you suggest cleaning the Mini? After each use, once a week? The instructions say that taking it apart and soaking the parts in diluted dishwashing liquid works, but doing that after every use would be a bit much.

    Thanks in advance!


    1. Hey Mal,

      Thank you so much for the feedback. Glad you like the Mini Mill! And yes, the meditative part of the “ritual” is the best.

      Generally, I clean my mini with a dry brush after every use to make sure it is free of old grounds. I do a more thorough cleaning with a little soap and water probably once every couple of weeks. I don’t always use soap either. Once a week does seem a little excessive. Enjoy!


  7. konafan says:

    Hey buddy, good review. I’ve been using the Hario daily for over a year now, grinding for a one cup Moka and I hadn’t thought of it as a meditative kind of thing, but I guess that’s right, time to slow down and enjoy the grind. Cleaning the burrs by grinding rice is an interesting tip, I bought some cheap white rice just to try that out! Keep doing what you do and enjoying the brew.


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