Brewzilla Gen 4 advice and experiences

[Davegase]

Cheers Dave, I’d never heard of that before but I’m in Herne bay so regularly in Canterbury. Thanks for the tip

You're welcome here's a screenshot of the water report I got from Murphy's for spotless water.

 

[MashBag]

Clever bloke once said.. Use a steamer

 

[peterpiper]

i have a quick question...i see some people dont bother with the top plate as it compresses the bed...so do you just have the recirc pipe hanging freely within the mash or fix it so it lays on top of the bed...i assume gravity will make it sink into the bed...does it matter if it sinks into the bed re effective recirculation?

I set the pipe so it's initially 2cm above top of the mash liquid (by twisting recirc arm, with pipe through lid hole), and use this point as a maximum level rise guide, when adjusting recirculation rate. Much more than 15mm can lead to a compacted grain bed. Having a layer of liquid above the grain, should even the flow over whole malt pipe area, better than a top plate etc.
I usually go for a thinner mash, and less sparge water, so usually have liquid over grain. Though might have thicker initial stage, of a stepped mash, where I'd be adding boiling water at step points.

 

[peterpiper]

Just finished cleaning up from another brew on the Gen 4. I made a 13L batch of saison -- 2.5kg of grains in 10L of mash water -- and decided to experiment with some simple step mashing to try to dial in some numbers. With the loose mash I had the pump around half open with no issues. For context I have the HED plate, jacket and BT thermometer.

Running at 35% power the lower probe showed an overshoot of ~1.5C after the cutoff temp (i.e. if the elements cut out at 62C, the lower probe temp would continue to rise to 63.5C). About 2/3rds of the total overshoot would end up being reflected in the BT probe reading a couple of minutes later. This was unsurprising once I thought about it seeing as the deadspace under the mash is 2.5L so that's a fair chunk of the total mash liquid being overheated.

With my initial allowed temp difference of 4C the overshoot at the top was >3C, which is a bit much as it takes 10 minutes or so for the temp to reduce again. I dialled down the allowed temp difference between the lower probe and target to 1C and the overshoot stayed down at 1-1.5C but for next time I think I'll set the allowed difference to target to 0 for small batches like this.

Anyway, things were learned, beer was made. Efficiency was fine at ~80% and zero other issues.

Your figures are interesting, and I'm glad someone else has noticed this happening.

With a given (grain bed) recirc flow rate - as diff setting and power are lowered, to reduce base temp overshoot, the time lag for correct temp in mash (at BT probe) will increase. With a 1°C diff, on a cold day & with slow recirc, I can imagine the core temperature decreasing rather than reaching target.

I've had the same setup, from day one with BZ G4 35l.
My main mash target was 65°C (but I guess from your figures that your using 60°C).

I used to have diff of 6°C, but doing a brew where only slow recirc was possible (a Hefweizen 60% wheat) the bottom overshoot was up to 10°C (if I recall right, at 60% power). And it took around 20min (after first base overshoot) for the temperature at BT probe to reach target (by when there'd have been around 4 base overshoot cycles). At that point I'd start the mash (step) timer.
The BT probe controlled mash temperature profile and duration will obviously be very different, to one done the inbuilt sensor alone. Which is right?

Most brewing lore, comes from days well before the arrival of BT probe thermometer temperature graphs. And even back then the best compromise rest temperature, between Beta-amylase and Alpha-amalase activity, was uncertain.

I'd previously brewed in a (borrowed) BZ 3.1.1 a few times, and was happy with the results. But after a few BZ G4 brews, including some repeated recipes from BZ3 days, I wasn't so happy. All seemed to have same kind of heavy/fuller feel, and remaining BZ3 bottles of Hefweizen were definitely superior to BZ4's. I'm thinking it must be from the higher temperatures, giving more unfermentable sugars, maybe with the beta-Amylase being denatured too soon.

I've now changed to 5°C diff, and amended my profiles so timer start alerts happen at 5°C before step target reached (at BT probe), and main mash temperature of 63°C.
I now also do 'outer recirculation' at max flow (outside malt pipe via lift hole, while 2nd recirc pipe off tap controls recirc through malt). Full flow, reduces base overshoot (beyond diff setting); shortens overshoot duration; warms grain bed from the side (rather than bed having to heat the surrounding unused static cooler water); the more diluted mash might improve efficiency slightly; full flow can keep flour and small particles in circulation until filtered through grain bed (rather than settling out on base, and burning later).

 

[peterpiper]

The beauty of the system is it gives you the flexibility and the information to dial in different setting parameters for different batch volumes.
But that flexibility is what a lot of users have problems getting the grips with.

Wish more flexibility and easier control was allowed. Such as:

Profile steps controlling power; diff °C (and others suggest PID also).
Printing/sharing profiles.

Change power steps to exactly 500W (20.8%) and 1900W (79%), in place of the 20% and 80%, and increase default relay cycle time, both to prolong circuit board life. The % powers are achieved by changing mark-space (on-off) ratios of the two heater relays on the power board. At 500W or 1900W, one relay would be permenantly on.
The JT105F-1 mechanical relay used for switching, has a life rating of 100,000 operations. That can easily be exceeded, especially if 'relay cycle time' is set too short. The default is/was 5sec.
If each relay has a 10second cycle, that's 6 cycles a minute = 360 per hour = 2160 per 6hr brew session = 101,520 per 47 brew sessions! to exceed its rated life.
Because of the mass of metal, any cycle time less that 20 to 30 seconds isn't going to increase heating accuracy much, just destroy relays sooner. (You might hear them clicking on and off as they operate.)

Easy control of running profile, with step forward; back and temperature control. & clear the step messages/alerts that can obscure the BZ screen (temperature readings).
Messages/alerts should be cleared when any button is pressed.
The cycle button normally cycles through three screen positions for: heat; target °C; and pump.
While a profile is running, a fourth cycle position "step" could be added (where superfluous _next - xx_°C or next - wait is presently displayed.
The cycle would then go: heat; target °C; step; and pump.
When control cycled to step, up/down should go to the next/previous step, perhaps with prompt: "press enter to confirm".
Override of running profile target °C, should be allowed.

Might help if more people reported issues or suggestions to the developers: gitlab.com/rapt.io/public/-/boards/ or RAPT portal - my account - issue tracker. Or comment on existing issues there.
They seem fairly good at responding.

At least since last update,the BZ4 now seems able to work if the wi-fi is off.

 

[Baldylocks Brewery]

I now also do 'outer recirculation' at max flow (outside malt pipe via lift hole, while 2nd recirc pipe off tap controls recirc through malt). Full flow, reduces base overshoot (beyond diff setting); shortens overshoot duration; warms grain bed from the side (rather than bed having to heat the surrounding unused static cooler water); the more diluted mash might improve efficiency slightly; full flow can keep flour and small particles in circulation until filtered through grain bed (rather than settling out on base, and burning later).

Hi Peter, I like this idea but you must have stuck with the original pump piping layout ?
I changed my config to the alternative so only recirculating arm is pumped (so I could still use the tap when pump got blocked).

What you say about the mash temperature overshoot is making sense as my beers since going G4 have been fuller and lower abv compared with older batches of the same. BT probe arrived this week but not used it yet so all G4 brews have been using internal temp probe.

I’ll test BT probe and split recirculation this weekend and see what happens

Any basic power/ temp recommendations welcome as I’m not so experienced with AIO controllers and I’ll factory reset the machine to eliminate any changes I’ve made so far.

 

[brewsby]

Hi Peter, I like this idea but you must have stuck with the original pump piping layout ?

It is an interesting idea. If I did it I'd probably go with a Y/T hose splitter off the recirc arm rather than run another line outside the unit from the tap though.

That said I'll fiddle with the other settings first. I'm not that paranoid about precise mash temps and if I think the best overshoot I can achieve is causing lower fermentability than I want (or the "BT" temp doesn't match standard mash temp vaslues hypothesis is true) then just offsetting my target seems easier.

Might help if more people reported issues or suggestions to the developers: gitlab.com/rapt.io/public/-/boards/ or RAPT portal - my account - issue tracker. Or comment on existing issues there.

Yeah, I've taken a look and I'll add issues when I think I've got a solid grasp on something. There was talk at one point of them open sourcing parts of the software but I guess that's not happening at the moment. The system seems ripe for an open source controller at some point seeing as the controller unit is just on a socket.

 

[The Baron]

I do not seem to have many issues now with my mash issues. I do set of at 5 diff for reaching mash temp and go 1 degree higher to allow for temp drop when mashing in then drop the diff to 1 for the mash and adjust re-circ flow to suit.
I then raise again to 5 for mash out and boil.
The only issues I find are crush that affects the flow(flow is the key on this machine) especially when getting to the bottom of a sack but it does depend on who I get the crushed grain from some are not a issue but others have more flour in the crush then just add some oat husks to help.
I have got a mill and will start to crush my own as I think this will help with flow.

 

[Baldylocks Brewery]

It is an interesting idea. If I did it I'd probably go with a Y/T hose splitter off the recirc arm rather than run another line outside the unit from the tap though.

Hi Brewsby, I’m thinking T hose splitter may be a good option to try

 

[tondy79]

Change power steps to exactly 500W (20.8%) and 1900W (79%), in place of the 20% and 80%,

I think this has been updated in the latest firmware release. Also, if you put it into "distillation" mode, then it will only cycle through these "complete" power steps instead of scrolling through the others.

 

[peterpiper]

It is an interesting idea. If I did it I'd probably go with a Y/T hose splitter off the recirc arm rather than run another line outside the unit from the tap though.

Advantage of using original plumbing, other modified with a Y ot T piece, is that you have the two valves to control flows across the two recirculation paths. I always pump out the finished wort, rather than having to elevate a full BZ to drain wort. And only use bottom tap as unpumped drain, for the final stage of cleaning.
The slightly larger diameter hoze I've got on the bottom tap, gives a much faster flow rate than the original recirc hose, making pump out quicker. And length allows it to reach higher (up o to fermenters on a workbench).

My appararant pump blockages, were nearly all while mashing, when they could be cleared by blowing back through recirc hose (with pump off). And I've a feeling these were just airlocks, rather than blockages. These never happen now, since changing my mash method.
Only once, did I have a real pump blockage after boil, and that was when 'helper' put hop pellets straight in, rather than into my large hop spider.

 

[peterpiper]

I think this has been updated in the latest firmware release. Also, if you put it into "distillation" mode, then it will only cycle through these "complete" power steps instead of scrolling through the others.

Hadn't noticed, last week, but will check when home.
I've never tried selecting 'distillation mode'.

 

[peterpiper]

I do not seem to have many issues now with my mash issues. I do set of at 5 diff for reaching mash temp and go 1 degree higher to allow for temp drop when mashing in then drop the diff to 1 for the mash and adjust re-circ flow to suit.
I then raise again to 5 for mash out and boil.

Will be good if diff setting option, eventually gets added in RAPT profile controls.