Even the mash on a Brewzilla G4 is going to take up a lot of the users input. Like any other SVB they need to be nursed through the mash. For instance, the Rapt BT thermometer can help control the core mash temperature, but it can't, The PID control monitors and adjusts temperatures, yes it does but only where the probe is.
I have been using an SVB since 2017 not counting the BM since 2011, which restricts a hands-on approach. Over that time I have learned that mash temperatures are different all over the mash tun. There are hot and cold spots throughout, for instance doughing in takes approximately 15 to 20 minutes of constant stirring for the mash temperature to become uniform throughout. Stratification in water and indeed the mash is well-documented, but not only that it is the heat absorption of the grain that is allowed for in the dough in temperature is included in the 15-20 minutes.
Grain crush is another part of the mash which contributes to the accuracy of the mash. I was intrigued by a brewer who stated 20 minutes stir then a mash rest of 45 to 60 minutes, also the saccharification times of different grains, some as low as 5 minutes!
A few weeks ago I tested this on my usual grain, crush for the base malt I was using saccharification time was 15 to 20 minutes, I tested my mash at the 20-minute mark with an iodine test, and sure enough, it was done, not that I would reduce my mash times just yet.
I repeated the same brew last Thursday this time with what would be called a perfect grain crush, now all grains aren't of equal size so getting the perfect crush for a home brewer will leave a percentage of the grains without a scratch.
Here are the results.
My usual crush after 20 minutes using the iodine test.
View attachment 94080
The "Perfect crush" over a one-hour mash. The samples were taken at 15 minutes, 20 minutes, 30 minutes, 45 minutes and 60 minutes top left-hand corner. If I had checked the grain after 60 minutes before mash out I am sure I would have found pockets of unconverted grain. Needless to say, the efficiency was far superior on the grain which was milled just a tab over the gap of the "Perfect Crush" I will also mention that I did stir throughout the 60 minutes intermittently keeping the temperature stable.
View attachment 94081
My biggest worry is if I owned a Brewzilla 4G is the long heat exchange taking place from the pump up the return pipe and the big gooseneck. Easily fixed with some lagging.
Sorry for the long post but marketing hype isn't meant to be fair dinkum.