The trouble is the Fresh Brew takes its sweet time to get there, typically requiring about five minutes to hit the 200 degree Fahrenheit (93 C) mark. This is much longer than other machines, such as theand which ramp up their water temps to 200 degrees (F) in two minutes or less.
Compounding the problem is the Fresh Brew's lengthy brew cycle. The machine needed an average of eight minutes and 21 seconds to finish brewing eight cups of coffee (specifically 42 ounces, or 1.2 liters). That's definitely outside the SCAA's strict home brewer certification guidelines of four to eight minutes. While correct brewing temperature is essential, so too is brew time. Steeping grounds too long in hot water will lead to liquid that's over-extracted and undrinkable, at least to me.
Sadly, Zojirushi's device suffers from this weakness. Coffee I made with it was consistently bitter and unpalatable, and refractometer readings confirmed this. Java brewed from my test beans (Costco House Blend, medium ground with a burr grinder) typically had a TDS (total dissolved solids) of 1.8 percent. This is more than the ideal TDS percentage (between 1.15 and 1.35) outlined by the SCAA and translates to an extraction figure of 30 percent -- well beyond the sought-after drip extraction factor of 19 to 22 percent.
Of course TDS numbers aren't the whole story. For example, theturned in very high TDS results, upward of 28 percent. That said, by design the Siphon Brewer exposes all its grounds to 200 degree (F) water quickly, with a relatively brief brew time of about 5 minutes, 30 seconds. Essentially the rich drink it creates is filled with tasty organic compounds, not noxious and over-extracted dregs.
I can say the same of the delicious java themade with the same beans. Though coffee it made had a TDS percentage of 1.28 and an extraction percentage of 26.8, the result was packed with flavor, with no bitterness.
Running premium grounds through the Zojirushi Fresh Brew didn't improve matters either. Pricey unwashed Ethiopian beans from local purveyor Heine Brothers yielded a powerfully bitter pot of coffee. That's a huge contrast to the bright blueberry notes and pleasingly complex concoction I've tasted when I've used the same beans in both the BV1900TS and Technivorm Moccamaster KBT 741.
The Fresh Brew's advanced thermal carafe didn't disappoint though. The container kept its contents nice and hot, above 150 degrees Fahrenheit (66 C), for over 13 hours.
I confess I had high hopes for the $190 Zojirushi Fresh Brew Plus Thermal Carafe coffeemaker. Based on the company's history of building quality rice cookers, plus its experience in constructing advanced vacuum-sealed thermal kettles and water heaters, I was expecting an exceptional coffee machine. Unfortunately, this was not to be.
While the Fresh Brew does have the ability to heat water to the optimal temperature for coffeemaking, it takes too long to get there. Add to this a lengthy brewing time, and the result is coffee that's bitter to the point of being undrinkable. For the Fresh Brew's same steep $190 price you're much better off splurging on the $190, which creates truly excellent coffee. High-rollers of course can choose the $250 that makes a distinctively delicious cup, or the $299 which brews just as well and keeps its coffee hot all morning.