Spong Coffee Mills: A Grinder for the 23rd Century

Grinders are one of the keys to exceptional espresso. Discuss them here.
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#1: Post by DJR »

Spong Coffee Mills: A Grinder for the 23rd Century

I first became interested in Spong coffee grinders (mills) about a year ago - I noticed a Spong No. 2 on Ebay and bought it for about $15.00. Like many of the Spong grinders I've seen since, it appeared almost unused. I guess people either get them as presents and don't use them, buy them on impulse and feel they're too much trouble or buy them for decoration.

Why use a Spong hand grinder?

There are a few compelling reasons. I have a Rossi professional electric grinder that works fine. Except it is larger than my espresso machine. Except that is very loud. Except that it retains over a gram of grinds. Except like most electric grinders, static causes a layer of coffee to stick to the doser. If I count the endless cleaning, brushing, blowing, and counter cleaning, the Spong takes less time and makes less mess and makes less noise than an electric. It also doesn't heat the coffee as it grinds. It will also never wear out, at least not in your lifetime nor your grandchildren's.

The quality of the Spong shot is at least as good or better than with a dialed in Rossi, which while not a quality benchmark, has been (and continues to be) a workhorse grinder in hundreds of thousands of coffee shops. The burr size on the No. 3 and 4 make even the Titan grinders look puny. I believe that most people who buy expensive commercial grinders for home assume commercial grinders deliver better quality because they are commercial grinders.

This simply isn't true for home use. Commercial grinders in a home setting have many disadvantages, aside from noise and taking up counter space: If you allow a gram or two of stale coffee that was left in your electric grinder to pollute your freshly ground shot; you'll have worse coffee, not better. It's like assuming that a backhoe will work better than a shovel in your garden because it is "commercial duty". What a coffee shop values in a grinder is not what someone searching for the perfect shot is looking for. The coffee shop needs idiot-proof high throughput and no downtime. They don't usually care about grind retention because the grinder is in constant use and at the end of the day can be cleaned (or the first customers can get double lattes).

Why not use a hand grinder?
If you have a lot of coffee to grind, it is more efficient to use an electric grinder. But if you use the electric grinder you will still have to clean it and that takes time and makes a mess, which also has to be cleaned. A clean grinder is essential. If you amortize the few minutes you spend cleaning over hundreds of shots pulled that day, it is not a big deal. But amortized over a few shots a day, you will spend more time cleaning than grinding and drinking.

Ultimately, however, quality issues being equal, perhaps the most important reason I use the Spong for espresso is that it appeals to me aesthetically. I use a 1970s spring lever espresso machine (La Peppina) which is silent except for bubbling water. Using a loud large electric grinder simply didn't seem right. It did seem ok when I was using a Gaggia Classic - noisy in its own right and high maintenance.

History and Models

Spong & Co., founded in England in 1856, made four mills, named creatively, Numbers ("No.") 1-4. . I don't have a No. 4 yet; maybe someday. First released c. 1895, they seemed to have undergone minor changes until the 1980s, when after the Spong family sold part of their business to Salter, the grinders were eventually discontinued.

Some believe that the No. 3 is for grinding large amounts of coffee and the smaller versions are for smaller amounts. Actually in my tests, the No. 3 is ideal for espresso given that it grinds 14 grams in 30 turns. The No. 2 takes twice as long or a bit more. It is simply a matter of burr size. When I have a chance I'll thoroughly test the No. 2 for grinding drip coffee, but I suspect that the best grinder for both drip and espresso will be the No. 3 or maybe the No. 4. My No. 1 is just to keep the others company.

There are a few similar or identical grinders released by other companies. Some were private brands under some OEM arrangement with Spong. An interesting one, with the name, "Mimoso No. 3" was made in Brazil. It looks almost identical to the Spong, though the Spong was not used as a casting pattern. It has an "S" curved shaped handle which is threaded to the burr shaft. My Mimoso No. 3 has the word "Brasil" cast into back, but a label with "Brazil" on the front, indicating that it was made for Brazilian domestic use, but was also labeled for export. Early Spongs also had "S" curved handles and were similarly attached. Later Spongs (probably starting around 1910, give or take a decade) featured straight handles attached via a square socket and screw. The Mimoso also has a single ball bearing behind the adjustment screw, but it isn't captured by the end of the burr, which is left to have some free play. The Mimoso is quite a bit heavier than the Spong and the counter clamp is not hinged and is slightly smaller. None of these differences are material, unless you have a very thick counter.

The Mimoso No. 3 has a burr the same diameter as the Spong No. 3, but the pattern of the teeth is quite different; the Mimoso having a more aggressive or coarse pattern initially, getting finer at the edges. The Mimoso grinds finer than the Spongs, using the same number of turns; it is easy to grind fine enough to choke the machine. On the other hand, Spongs cannot grind Turkish. Spong seemed to change its logo over time. It also began with the word "London" cast into front right periphery, later changing to "England" and sometimes with no mention of origin.

Spong burr on the left; Mimoso on the Right

Mimoso ball bearing on back plate. It isn't a trapped ball, however, so it functions just like the Spong.

Another similar grinder under the name Beatrice also appears with a curved handle similar to the Mimoso. Beatrice, which sold other kitchen items similar to Spong, and Mimoso all seemed to share the same numbering system. In the 1980s, Salter made at least some grinders without the Spong & Co. Name appearing around the outside. I have a No. 2 and it is identical to the Spong-labeled grinder and only about thirty years old. All of the above grinders are made of cast iron using sand casting techniques and none of them are hardened.

For more information about Spong & Co. see http://www.gracesguide.co.uk/wiki/Spong_and_Co.

Another interesting article including information about the Spong family can be found at: http://www.felbridge.org.uk/index.php?p=2_27

I have PDF versions of the above articles should the links die; you can contact me for them.

Comparison to other hand mills
I own several other hand powered coffee mills: Zassenhaus, PeDe (Peter Dienes), a Japanese version of the Zass, and several American mills including Arcade, Enterprise, Landers Frary & Clark, and Parker. After some use, I have completely ruled out (except for traveling) table or lap mills. They are simply too much trouble for me. Perhaps if I was making coffee for one, but even so, I find them annoying. A lap or table top mill requires the user to grind as if stirring a pot while holding the mill still. The harder you stir, the harder you have to hold onto the mill.

Here is a shot showing from left to right, a Spong No. 3, Spong No. 2, Zassenhaus and modern Asasco. Notice the white spray paint overspray on the Spongs.

Wall mounted or table-clamped mills, however allow you to crank as hard as you want while the mill is firmly held by the wall or table. The result is not only is it easier, but the more efficient transfer of energy allows for the use of a much larger burr (more surface area) with less work. In fact, the burr size of the No. 3 Spong is almost twice the size as Mahlkoenig Guatemala Lab commercial cupping grinders costing more than $2500. Not to belittle the Mahlkonoenig; I'm sure it is a lovely and more than capable grinder, but it does operate at 3400 RPMs, which is enough to warm the coffee, it has only a one year warranty (I'm sure they last for many years) and requires quite a bit of cleaning and maintenance. The Zassenhaus and other lap mills have tiny burrs for a simple reason: if they were any larger they would be impossible for a user to hold the mill and turn it. The handle, again because it is held in the lap also has to be short giving much less leverage and requiring correspondingly more effort.

Wall mounted mills are also cleaner (you grind into a glass or metal container, not a drawer which tends to trap grinds behind the drawer), and above all they are fast. My No. 3 Spong will grind 14 grams for an espresso in 30-40 easy turns and a couple back spins to make sure there is no grind retention. I measured the amount of grinds in the No. 3 and it was less than 1/10 of a gram after three months of use.

Why are the Spongs so efficient?

Aside from the improved ergonomics, the most important reason, is that they have huge burrs compared to the European lap mills. Several times the grinding surface. The geometry of the burrs is such that they bring the beans through progressively smaller ridges and no bean is left behind (unlike some of the European mills where a stray bean or two often is stuck somewhere).

Can the Spongs grind espresso?
Definitely. They seem to do it differently than the European mills. The latter have more or less hardened, sharp, precision burrs and bearings and resemble the burrs in prosumer electric coffee grinders. The Spongs are a joke precision-wise. They have slop. There are two bearing surfaces, one at the back which is not captured and the shaft in the front. Both have a lot of play. I couldn't resist modifying one with a captured back bearing and I made it precise! Was it better? NO! I had to undo the modification. The built in slop is necessary because the two burrs don't precisely mesh in the first place. The burrs, unlike the European are cast, not machined and are similar to the American mills. They are not precision castings. They are in fact, quite sloppy. But they work.

Ultimately, I'm not 100% sure why they do. One thought is that the rear bearing surface allows the burr to find its own sweet spot automatically. In other words it allows a certain eccentricity to the movement and in that sense is self-centering. Regardless, it works much better than the European mills.

Can the Spongs grind drip coffee?

They can, but I have not had time to fully experiment with them. I currently use a 100 year old American-made Arcade Crystal No. 3, also from eBay, bought without glass for less than $20.00. I didn't want the glass. I grind four scoops of coffee directly into the paper filter in 40-50 turns, with basically no grind retention. It won't however, grind fine enough for espresso.

Adjusting the Spong for espresso
The adjustment is via an L-shaped screw at the back of the grinder. There is a small nut with a tail on it that serves to lock the screw once you have the grinder adjusted. Here is what I've done with good results: tighten the screw until the burrs are not only touching but are actually hard to turn. Then turn for awhile. Tighten. Turn some more. You can even put a power drill on a nut that is screwed into where the handle attaches. The idea here is to break the grinder in and get the burrs close enough to do espresso. In my experience, rubbing burrs doesn't wear them out. As you turn the handle and tighten the screw feel the resistance of the burrs rubbing. It won't be even-there will be areas that seem loose compared to the other hours of the clock (if you think of the burr as a clock face). It is about right when you can feel a slight resistance over most of the turn - I'd say that there shouldn't be more than two areas that are about two hours (a total of four hours) where the burrs seem loose.

Throw in a scoop of beans and check the powder coming out. When it is fine as fine cornmeal, pull a shot. If it needs to be finer, adjust it finer. I've found that it is easier to creep down on a shot than to creep up-meaning that it is easier to back off from a choked basket than the other way around. I have my No. 3 adjusted so it will create a 25 second pull (not counting a 20 second pre-infusion) on my La Peppina. Once you've made the adjustment to your liking, tighten the lock nut. I tend to tweak it if needed, but often it isn't necessary. The shots come out with plenty of crema, tiger flecking and are more than satisfactory.

Disassembling the Spong

They only have two moving parts and counting the handle only four parts, plus the adjusting screw, altogether. (The funnel does come off, but no need to do that, ever, unless you're painting it.) The No. 2, No. 3 and No. 4 Spongs have four machine screws around the periphery which are removed after first removing the handle. The No. 1 has two screws. Use a LARGE screw driver. The screws, while large, are soft. Also at this time, loosen the adjusting screw so when you reassemble, it will not be putting any pressure on the burrs.

You can clean in the sink, wet or dry, using wire brush or old toothbrush. If you use water, use a hair dryer to dry it off. Wipe the parts that don't touch coffee with a bit of any sort of kitchen oil to retard rust. Put a bit of oil, Vaseline, Chapstick or something similar on the end of the rotating burr where it contacts the adjustment plate. That's it. Reassemble in reverse order and you're done. Since grind retention is minimal, you don't have to do this often. If your grinder came packed with grinds, the former user was either not doing a few back turns to clear the burrs, was using very oily coffee and perhaps was filling the funnel up with beans and grounding them as needed. This latter technique is something I don't recommend if you care in the least about how your coffee tastes. I also don't recommend using the grinder for very oily roasts. If you are roasting to Vienna there is no grinder that won't get gummed up with the coffee.

Restoring a Spong

Occasionally you'll see a Spong that is quite rusty. Or missing the adjusting screw. It is a simple matter to replace the screw. Any ¼-20 bolt along with a thumb nut to act as the lock nut will work fine. Rust is also easily fixed. Since the grinder isn't a precision tool in the first place, all you have to do is remove the rust. Don't use a chemical rust remover. Take apart the mill, brush it with a brass or other metal brush and if there is a lot of rust, immerse it for several days in a solution of 1 part regular molasses and 10 parts water. It won't damage the paint, but will take care of the rust. Don't laugh. Don't check it for a few days. Then remove the pieces, rinse in the sink and use the brush again. The rust will be gone. Really gone. So gone that once you dry it with your hairdryer, it will rust almost immediately if you don't put a thin coating of cooking oil on it to protect the unpainted surface. It will then be as good as new. Maybe better.

Catch Cups
I have never had an original catch cup. They are usually missing. When they are present, they usually add significantly to the bid price. A piece of printer paper works to catch the grinds and then makes it easy dump into the portafilter basket. Lately I've been learning metal spinning and make catch cups, including one with a built in funnel for my La Peppina portafilter.

Buying a Spong
I bought all mine from Ebay. They've ranged from $16 to $50, though sometimes they sell for over $100. However, if you wait and watch, you'll be able to get one for $50 or less. Try to get a picture looking into the grinder. If the funnel is clean and white, it is likely to be almost unused. Many have rust or heavy coffee stains. Given that a few are almost always for sale, there is no reason not to wait a bit and get a nice one. Get at least a No. 2 or No. 3, preferably the latter. I hope this article doesn't cause a run up in price. They are not very rare.

[This article is a draft.1.1 (Will finish uploading more pictures in the next few days0]

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#2: Post by orphanespresso »

Very nice document about the Spong...well done and congratulations as with these types of magnum opus works one can think about it for a long time before committing words to page. As you call it a review I do not know if it is appropriate to comment as it may be meant as a stand alone piece but....
We once pursued the Spong line on ebay as you say, the source, but indeed again as you say they are seemingly unused or in such good condition that they seem new....even the paint was generally perfect, and missing the catch cup, yes. As lifelong antique collectors/dealers we became suspicious that some of these grinders may be reproductions. Do you have any feeling or evidence for that possibility? There was a rumour that Spong was being knocked off but we never found substantiation, just an odd feeling that the ones we had did not grind as well as they should have. Certainly none of ours was suitable for espresso.
We like the counter clamp feature and you are correct that the counter mill does require more exertion to both hold and turn but the well centered bearing and two point bearing (at the top of the axle shaft under the handle and below the bearing in a centered post) does lend a lot more logical stability but again, your observation of the failure of the grinder to produce a good grind when forced into absolute alignment is spot on. I believe this has to do with burr loading which tends to push the inner burr out and create a fairly uniform space between the two burrs as long as the burr is uniformly full all around....in the beginning and at the end of the grind the load becomes uneven. We think this is the point when the burr when set on coarse begins to fine out....the beginning and the end of the bean dose cause a lot of inconsistencies of grind if there is no design feature to compensate for this.
We have observed a similar refusal to perform when forced into alignment of almost all of the hand mills we have had as they seem to need some 'slop' for the grinds to exit efficiently and there is always one spot of burr touch on any setting but the most coarse....as I tune the burr by feel and sound they usually come out grinding at their optimum level, but this idea is a bit too Old World for some....a burr that sounds good on the grind will grind good and one that sounds harsh will not grind well....there is a lot of mysterioso with hand grinders. We are putting the final touches on our own design for the ultimate hand grinder and have had to design this mysterioso effect onto the mechanism...the old grinders just did it but these days one has to proceed with more geekdom than they used in the past. I think that an electric burr grinder does not have this slop and the cutter faces are in much tighter alignment made possible by the use of a lot of power to turn the burr and grind evenly...no wobble or slop here, as they would tear themselves apart!
The wall grinders that you mention suffer from the same difficulty as any horizontal axle grinder which is the efficient loading of the burr and feeding of the beans into the burr. This solution to this problem can be best seen in the big side crank box mills which have a worm gear feed before the burr which forces the beans directly into the burr and help reduce the number of unloaded burr cranks on both ends of the dose.
Since the Spong has a horizontal burr the development of even load over the face of the burr may take a turn or two and the last turn or two may see the unloading of the burr, again, can't be helped. Your Burr photos show a reasonable similarity to the Moulinex burr...the aluminum body art deco mill that we see on ebay-France a lot but the Moulinex has a tool steel burr and not a cast iron burr....it is a very good coarse grinding burr....French Press, of coarse!
Again, congratulations on your work and thank you for setting it all down for all time on Home Barista!


#3: Post by earlgrey_44 »

I have a dusty old #2 in a box down in the basement. I bought it new from my store's inventory almost thirty years ago. I used it for maybe six months for drip back in the day, then replaced it with an electric wiz-bang.
DJR wrote:Can the Spongs grind espresso? Definitely.
orphanespresso wrote: Certainly none of ours was suitable for espresso.
I'll drag it up and see if I can get it in the zone. I'm curious to see what it can do for the e-61...
Trust your taste. Don't trust your perception.

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DJR (original poster)

#4: Post by DJR (original poster) »

Spong Knock Offs


Thanks for your kind words. Regarding knockoffs, I can't prove a negative, but I believe that the Spong has not been knocked off in recent (Chinese foundries) years. Here is my reasoning:

1. All Spongs I've seen come with remnants of a label telling the user to do some 'empty grinds' to clear the grinder. Often the remnants are only a trace of adhesive left on the funnel. If the grinder was being copied, I doubt that they would include a remnant of a label. They would either skip the label or have a nice one which would increase the 'collectability'.

2. All Spongs I've seen use US threads for the screws. This was common in England at the time. If it was being made in China, there would be a temptation to use metric, as the iron foundries usually use metric.

3. All Spongs I've seen or seen pictures of show some white "overspray" on the moving burr. This is because it was painted after assembly. The reason for this is probably that if it was sprayed before assembly, any drips or overspray on the mating surfaces would have to be cleaned off. Initially I was suspicious of the use of spray paint but it seems that spraying paint was invented at almost the same time as the grinder itself 00 1893.

4. Parts reduction -- modern casting techniques would make it tempting to cast the funnel and the outer burr as one assembly. Shell casting could do that. However, all Spongs have those components in two parts. The clamp is also another, hinged part. That could be cast as one piece too, as the Mimosa does, again reducing costs substantially.

5. Normally, the knockoffs are sold by Ebay sellers who have stores and sell a lot of other crap. I haven't found that to be the case with the Spongs. I also have never seen a seller sell more than one. If they were being sourced, I think we'd see a different trend. For example there are some Frankengrinders that are probably made in China, all with slightly different boxes and seem to be roughly based on a Peugeot design??

6. The catch cup adds a lot to the sale price of the grinders. They would cost almost nothing to make. I'm making them, but that would cost a lot! It would be tempting for a knockoff supplier to supply some sort of catch cup and make more money.

Here's a shot I pulled with my La Peppina, which I got from Doug and Barbara. Ground with a No. 3 Spong

Here's another No. 3 Shot. There's no doubt that it is making espresso...!

7. If one wanted to knockoff the Spong it would be tempting to use the existing parts as patterns. That is done for junk 'Americana' axe heads etc etc. I haven't done careful measurements, but the resulting casting would be a few percent smaller due to shrinkage. I'll measure one of these days....

Thanks again for your thoughtful response.


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#5: Post by Carneiro »

Fantastic post Dan, congrats!!!

Sorry about no information about the Mimoso that time you asked me. After you wrote me, I looked around and saw some Mimoso on auctions website but I don't know the condition of them. There is one company here that still makes something similar to the Mimoso, I'll try to gather more info.



#6: Post by earlgrey_44 »

earlgrey_44 wrote:I have a dusty old #2 in a box down in the basement.

I'll drag it up and see if I can get it in the zone. I'm curious to see what it can do for the e-61...
Well, to my surprise, the #2 was actually a #1. :(

Decided it wasn't worth the effort to mess with it.
Trust your taste. Don't trust your perception.


#7: Post by strfish7 »

Well, based on this article (and my own curiosity) I bought a No. 2 this week on ebay. We'll see if it works as advertised. Thanks for the extensive writeup.

Howdy Mr

#8: Post by Howdy Mr »

I've been curious about these and watching them on eBay as well. The idea of a wall grinder appeals to me both aesthetically and for ease of use. But I've read little about them. Some of them are beautiful, so that even the missus wouldn't mind one mounted in the kitchen.

There are a lot of number 1s and 2s on eBay, but I haven't seen 3s. I'll have to keep my eyes open. Thanks for the research and clear description Dan.

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#9: Post by yakster »

I found a reference to a fifth size, the number 0, which is rare. This Polifrog Blog shows a picture of the number 0 size and some history of the grinders.

LMWDP # 272

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#10: Post by narc »

The 1st grinder owned was a Spong #2 or #1. Purchased slightly used back in '81. Very small apartment kitchen with minimal free space to clamp the grinder. Daily routine of clamping, unclasping placing back in storage space. Got lazy. Ended up purchasing from my friends shop another returned slightly used Salter/Spong pictured in the "Hand (grinder) Jive" thread. The Spong is somewhere in storage or was left during a move.

Thanks DJR for the photos and history lesson.
LMWDP #151