Perusing eBay today, I came across a listing for a new-in-the-box rectangular slow cooker. Never one to pass up a chance to check out a box or packaging for details and clues, I clicked through the pictures.

Mark your calendars! Starting next week, Merry Mushrooms unicorn pieces will go cap-to-cap to find the most sought after, most intriguing, and most unique Merry Mushrooms items. There are so many to choose from, so your favorite may not have made the cut. This is all in good fun, so vote away! 

Download and fill in your own bracket to play along! Come back to this blog each week and vote. For reminders, like and follow A Collector's Guide to Merry Mushrooms on Facebook.

Round 1 voting will be open Monday, February 28 at 10am to 8:00PM CST Saturday, March 5.
Round 2 voting will be open Monday, March 7 at 10am to 8:00PM CST Saturday, March 12.
Round 3 voting will be open Monday, March 14 at 10am to 8:00PM CST Saturday, March 19.
Final Round will be open Monday, March 21 at 10am, closes 8:00PM CST Saturday, March 26.

Back in November, my attempt to unravel the large/flour canister and cookie jar conundrum turned out to be just the first step of what will likely be a long journey. As part of that investigation, I discovered that the lids of the embossed ceramic canisters were constructed in two different ways.

One of my large canisters measures 10" tall and 7" at the widest point of the base. Based on measurements, it is a large canister from 1985-1987.  The lid of that canister also has an opening on the underside (lid on the right in the photo above).

Looking at the mushroom knob from the outside, the difference in construction is apparent. The mushroom knob on the left below is attached with clay slip and doesn't look fully attached (no opening) when compared to the knob on the right (has opening).

Embossed ceramic Canisters and Cookie Jars, if they are marked, are dated 1975, 1976, 1977, 1978, and 1983. There may be other dates out there, so let me know if you see one! Surveying canisters online that have pictures of the inside of the lids, only the ones dated 1983 have openings in their lids.

While this is an exciting discovery, it leads to another mystery because of course it does! My large canister that sure seems to be a mid- to late-1980s canister is marked not 1983, but 1978. Huh? Is this a 1983 lid on a 1978 bottom? Did this one get accidentally marked 1978? The most likely solution is that the lid and bottom are not original to each other, which could also account for the difference in overall height (bottom + lid),

Since the embossed canisters raised the question about openings in the lids, do any of the other pieces that have mushroom knobbed lids have openings? Would this be a way to date Merry Mushrooms? Would only the later pieces have an opening?

​The Beverage Server (1971-1974) and the Spin Canister (1971-1972), both available for a brief time in the early 1970s, proved otherwise; the Beverage Server does not have an opening but the Spin Canister has a rather unique opening (see caption below). The uniqueness of the opening is probably due to the sheer size; as the largest mushroom knobbed lid, the partially covered oval opening gives support and stability.

The Sugar Bowl and Creamer Sets were offered the entire run of the line, though they weren't marked until around 1976. More on marks here. The marked Sugar Bowl's lid (1976 and 1978) and the marked Butter Dish lid (1978) have an opening. Finally, the unmarked Soup Tureens (about 1971-1975) have a small round opening, but marked ones (1977 and 1978) have no opening.

So, looking for the openings may not be helpful to determine date after all. However, it may help match the correct lid with a bottom if replacement is necessary.

By why the openings in the first place? The ceramic pieces including the lids were made by slip casting, a ceramic manufacturing process that allows for any shape with very intricate details to be made inside a plaster cast. A slurry of clay, or slip, is poured into the mold, coating the inside. After sitting for 10 to 25 minutes, the excess slip is poured out. Once the clay is dry enough, it's removed from the mold and set to dry.

Though this article is about identifying copies of Victorian ceramics, it provides a very good and visual explanation of the slip casting process. Where the openings in the Victorian example points to a copy of an original, for Merry Mushrooms they point to their enormous mass-produced nature. It's quicker to cast in one piece, and not two and then attaching the knob.

But, as we now know, not all Merry Mushrooms lids have an opening. Maybe it's the size of the lid; too small or too large is too difficult to cast in one piece. The Sugar Bowl and Beverage Holder lids are small and round, but only the Sugar Bowl has an opening so that doesn't seem to be it.

Talking with my manufacturing production author husband, Nate, the more plausible explanation comes down to what production capabilities at the factory had at the time. Even though it's most certain that more than one factory in Japan produced the ceramics (which I'm attempting to track down) for export, let's focus on one factory. In that factory, there are several production lines, all of which have machines and people that make the same end product but have different capabilities.

Slip casting molds do get worn and cracked with use so the factory has master mold or piece on-site to create new molds. It's possible that Sears provided a master mold as two pieces, lid and knob, and based on what production lines were in that factory, the mold maker could create the correct mold and stick will it. It's easier to make two pieces into one slip casting mold (refer to the Victorian ceramic article mentioned earlier) than one master mold into two parts.

Special thanks to the members of the Mad for Merry Mushroom Facebook group for providing pictures of the Spin Canister, a piece I can only dream of: Marti M., Ahn J., Brittany M., Sarah W., and Jenn S.