One of the most significant design flaws of the Brewzilla is the recirculation process. While mashing, when the pump is on, the wort in the mash is sucked down to the drain which is at the bottom, in the middle. Because the pump is strongly pulling this wort through this drain, most of the wort in the mash is pulled directly into the drain without it having a chance to be heated. Meanwhile, the liquid that stays on the circumference at the bottom, near the heating probe gets heated, and the Brewzilla thinks that the mash temperature has been reached, and turns the heat off. Thus the mash temperature continues to drop and it is most difficult and time-consuming to trick it back up again.
Kegland has come up with a solution to this issue, a cicular plate that fits under the bottom screen. The wort coming from the mash is forced to fall off the edge of this plate into the circumference of the bottom, where it then has to travel over the heating elements to pass through the drain.
But in North America (at least in Canada), this plate will not be available until this Fall. I think this plate will greatly help rectify this problem, although I wonder if it only works well when the plate is exactly horizontal (otherwise almost all of the wort will just fall off one edge of the circular flat plate).
In the meantime, a friend and I were trying to think of an interim solution. And then it hit us. If the pump is turned off for a brief time, the wort from the mash will drain straight down, rather than be pulled to the middle (as when the pump is on). It will then fall on the area above the heating elements. It will also remain on the bottom long enough for the heating elements to normalize the temperature of all the wort in the bottom. Once normalized, turning the pump on again will ensure that what gets ciculated back to the mash is heated wort, not wort at more or less the same temperature. This can be intermitently repeated.
Thus, it may work by setting the pump at a low percentage, perhaps 20 or 30%, which can be determined by experiment. This means that the pump will automatically turn on and off repeatedly, allowing heat exchange to occur much more efficiently.
Has anyone already tried this approach?