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. Cleaning
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]