Pattern: Solid Colors
Identifiers / Alternate Names: Various color shades, but all completely solid colored on the Pyrex item. Also known as: Primary Colors, Multi-Colored, Yellow Red Green Blue
Item Type: 400 Series Opal White Mixing Bowls Set
Years Manufactured: 1954
Values: Check below on Ebay for approximate prices
Sizes and ID#s: #401 (1.5 pint) #402 (1.5 quart) #403 (2.5 quart) #404 (4 quart)

These unusual pure white Opal Mixing Bowls are similar to the Primary Color Mixing Bowl set in size, but they haven’t been painted at all. I believe this is a bit more rare for the mixing bowls, although there are other types of glassware such as the refrigerator boxes and casseroles that may be more common.

This Opal White mixing bowl set consists of a four bowls: 1 1/2 pint 5 1/2 inch diameter, 1 1/2 quart 7 inch diameter, 2 1/2 quart 8 1/2 inch diameter, and a 4 quart 10 inch diameter bowl.

Interestingly, you’ll sometimes see Opal White bowls on Ebay that were offered in combination with third party items. These aren’t the standard 400 series mixing bowls but came with the Hamilton Beach Electric Mixers. These bowls look quite a bit different than the standard 400 size bowls; Many have a small spout connected to the lip of the bowl.

Here’s an example of a Pyrex mixing bowl in opal white found at a thrift store:

Pyrex Love - Opal White Bowl

Update 4/08: Since the time we wrote this 2 years ago, we’ve come to realize that the “true” Opal White mixing bowls may actually be different in shape and markings than standard 400 series bowls. Several readers from Pyrex Love Flickr, note that their bowls have no standard “pyrex stamp” on the back. In fact, there was nothing written at all, just an empty circle with a small number that is most likely a batch number.

Opal White 404 - Pyrex Love

We found a 404 four quart bowl that matched that description exactly the other day. I hadn’t seen one until we found that one.

Opal White 404 - Pyrex Love

As you can see, there is no standard mark and just a number. This makes me wonder if the little 401 bowl we found above, which DID have the standard mark, is perhaps a standard non-opal white 401 bowl that just had it’s paint removed! This is entirely possible, as many people have found bowls that have had nearly all the paint worn off. However, we just aren’t sure if the opal white set was NEVER produced with standard stamps. So for now, we’ll just say that it is possible it came both ways, although it definitely was produced at some point without any stamp.

Opal White 404 - Pyrex Love

Interestingly, we took another 404 bowl (Americana) and compared it to the Opal White 404 Bowl we found. The latter (on left) is definitely heavier - I could tell this right away just from holding it, but there is a marked difference in the photo above when you compare the width of the bowl walls.

It is also heavier - I weighed both and the Americana 404 came out to 3 lbs. even while the Opal White 404 was 3lbs 5.5 ounces. The diameter seems to be the same, however.

   Selected Pyrex items: