Osaka Slow Brew Dripper Review

INTRODUCTION
I recently started enjoying cold brew coffee at home. Straight from the brewer, slow, cold brew is delicious. This method of extraction is nearly acid-free and requires nothing more than a brewing device, ground coffee, and water (in liquid and frozen states). I can also attest, and have "witnesses," that it is a marvelous base for making homemade coffee liquor ("Kahlua").
I recently reviewed the Cold Bruer and have made around five or six batches with it. It is a beautiful device but has a couple of small problems. While it makes excellent slow-cold brew, the drip chamber (the area between the top of the coffee bed and the bottom of the dripping spout, is small. The cold water causes condensation on the inside wall of the glass making it difficult to ascertain the drip rate later in the process. The drip-rate adjustment is done by removing the lid but the condensation and lack of usable calibration lines or visible indicator makes that a bit of a guessing game. Still it makes a great cold brew beverage. It is a quality device, but at $80 may not appeal to those who just want to see if they like cold brew. I understand.
To fill that "starter void," A search led me to a number of cold brewing devices. There are a lots of full-immersion brewers selling in the $10 to $20 range. These use a fine-mesh basket that holds the ground coffee in contact with the cold water. At the other end of the spectrum are some wood and glass tower drippers that sell for well over $100 (and one sells for over $400!). But fortunately for us coffee-consuming mortals there are some affordable slow brewers.
I was specifically looking for a slow drip cold brewer that had more capacity than the "Cold Bruer." I wanted one that featured a design that made it easier to see as well as adjust the drip rate. During that narrowed quest I came across the Osaka Cold Brew Dripper. I received the small size Osaka for review.
This affordable device is designed in Japan and made it Taiwan. It consists of three main parts. From the bottom up, they are:

THE CARAFE
The carafe is the only portion of the brewer made of glass. All other components are plastic. There is an included pouring cap that snaps securely into place in the mouth of the carafe. The cap does not create an airtight seal so plan on saving any leftover coffee in a separate vessel. The carafe's markings are for the number of five-ounce cups (2, 3, and 4). The small size (seen here) has a maximum capacity of about 20 ounces, so two coffee drinkers can empty the carafe at one sitting without too much difficulty. There is also a larger size available rated at 6 cups (30 ounces).

THE BREWING CHAMBER WITH FILTER
The brewing chamber holds the ground coffee. The inset image shows the fine-mesh stainless steel filter located on the bottom of the brewing chamber. It is permanently mounted in the plastic and cannot be removed. There is also a separate stainless mesh filter which is included. This is placed on top of the coffee bed to assist in water distribution and to avoid the disruption of the coffee by the dripping of the water.

THE ICE AND WATER CHAMBER
The top assembly acts as the reservoir. It has a lid to make moving the Osaka Brewer easier as the lid can be held in place to avoid spilling. It also keeps dust and dirt out during the brew cycle. It does not snap into place so a brewing vacuum in the reservoir as the water is released should not be a problem.
The inset image shows the valve which is permanently attached to the reservoir. The shaft can be easily turned by hand to regulate the drip rate. The only confusion was that when the valve was in the position that places the grip horizontal, the valve is full open. Aligning the grip with the flow direction is full off. This is opposite of how most such valves like the gas supply and water main supply valves to your home operate.

BREWING TIPS
The Osaka website has a very handy Brewing Calculator. They recommend 8.75 grams of coffee per five ounces (1 cup) of water. They also give the excellent advice, "Measuring coffee by volume is not a good idea, since each coffee and each type of grind weighs differently." So for a full, 6-cup pot in the small Osaka Brewer, they recommend 52.5 grams for 30 ounces of water. I think they could have rounded off the .75 grams as most household scales that can measure in grams do not have tenths resolution.
With both of the slow/cold brewing devices I have found that it is best to grind the coffee and let it rest for a few hours before brewing. If the coffee blooms excessively it can displace the top filter. The expansion of the coffee in the Cold Bruer can be excessive enough to totally obscure the drip rate. I recommend allowing the coffee to rest after grinding and pre-wetting before beginning to brew when slow-cold brewing. For those who purchase pre-ground coffee this should not be a problem. For home roasted or for those who buy locally, freshly roasted coffee, I recommend a rest period after grinding.

IN USE
The Osaka Cold Brew Dripper is really easy to use:

Weigh and grind the coffee. As stated above, I recommend giving the ground coffee a few hours rest to allow a bit of out-gassing to minimize bloom. I tried a couple of other methods such as repeated pre-wetting and tamping before brewing, but that made no difference.
Dose coffee into the brewing chamber. Level and tamp a bit (not too hard or you might damage the filter below the coffee). Place top mesh filter on top the coffee bed.
Place brew chamber onto the carafe. Pre-wet the coffee with about two ounces of water slowly poured onto the top filter. Pour as to distribute the water over the entire coffee bed. Add water until the coffee is well soaked, but do not just flood the chamber.
Place reservoir on top of the brew chamber and close the valve. Add the amount of water and ice appropriate for the amount of coffee used.
Adjust the valve for the proper flow rate. They state that the rate should be about two drops every three seconds, or roughly 40-45 drops per minute So just set it to drip a little slower than one drop per second. About half way through the brew cycle you should check the rate again as it will slow down as the level of water in the reservoir decreases.
When the reservoir is empty, close the valve and remove it from the assembly. Take the bottom two-thirds of the brewer to the trash and remove the brew chamber and dump the grounds.
Take the carafe and enjoy a delicious cup of cold brew!

CONCLUSION
While the English instructions and test on the website could use a bit of help, the simplicity of the Dripper requires little detail in terms of learning how to use it. The simplicity of this review also reflects that as well.
The Osaka Cold Brew Dripper is available directly from Osaka for $35 for the small and $40 for the large. On Amazon the small sells for just $25 and the large for $30. I would recommend the large. Even at $30 for the large size the Osaka Cold Brew Dripper is a very affordable way to try slow/cold brewing at home. If you have not already done so, I do recommend it as a way to make a different and delicious cup of coffee at home (not to mention coffee liquor!).
Check out their other products as well. They carry an interesting line of immersion and pour-over brewers as well as pour-over filters, cups, mugs, a moka pot, and more.