I especially like the conical shape of this carafe, which strongly resembles an Erlenmeyer flask. Complete with graduated markings for volume (in milliliters and ounces) the glass could have easily come from inside a laboratory, not bundled with a kitchen appliance.
I had no trouble using the Oxo Cold Brew. The trickiest part was grinding the large quantity of beans (10 ounces, 284 grams) then transferring them into the Oxo's brewing container without creating a big mess. For best results these beans must be ground coarsely, so I had to run multiple batches through my relatively small domestic burr grinder and hope I didn't get clumsy.
Once the Cold Brew was fully loaded, I carefully added water (40 ounces, 1,200 ml), waited 10 minutes then gave the grounds mixture a thorough stir and returned its lid. Twenty-four hours later, I pulled the Brew-Release switch down to end brewing and drain my cold-brew liquid into the glass vessel below (a 20-minute process).
In the end, I was treated to 24 ounces (710 ml) of sublimely sweet, smooth, and rich coffee concentrate. Refractometer readings confirmed the complexity of my drink, which had a measured total dissolved solids (TDS) percentage of 5.4 percent. This is a high figure for any coffee drink, but when you factor in the massive amount coffee grounds consumed in relation to the brewing water (a 4 to 1 ratio of water to coffee), it translates to a low extraction percentage of 4.9 percent.
Don't be alarmed though, because unlike the 19- to 22-percent extraction (1.35 percent TDS) considered ideal for drip coffee brewing, cold brew is a different animal entirely. Brewing coffee cold is by nature a low extraction method and inherently lacks the acidity and bitter flavors often created through heat.
Whether the $50 Oxo Cold Brew Coffee Maker is a smart buy depends on how much you enjoy this unique coffee drink. From a purely economic perspective it pays to make cold brew at home rather than buying it from stores and coffee shops, which typically add on a significant upcharge.
With Oxo's device I could theoretically squeeze five 24 ounce cold brew batches from a 3 pound bag of Kirkland Costa Rica coffee ($15 at my local Costco). 120 ounces in all -- that's a much better deal than forking over $7.99 for a 32-ounce bottle in the supermarket.
Of course if cold brew isn't part of your regular routine, I don't recommend dropping $50 on a highly specialized kitchen gadget. You'd be better served by a $30 Bodum French press which can brew hot and cold coffee. Another affordable option is the $25 Takeya Cold Brew Coffee Maker, though I'll reserve final judgement until I personally take it for a spin.