Brewzilla Gen 4 advice and experiences

6Trails · Aug 27, 2024

foxy said:
I run my system with the top and bottom sieve plates together at the bottom, my next brew I will be trying a fine sieve between the the two plates so I can mill even finer and get more bang for my buck. I'm not sure how it will go as being dependent on gravity may not work. But I will never know if I don't try.

I tried the bag outside the malt pipe once but what I found was that flour went through the plates but all gathered in the bag instead of coming back up top, ended up completely restricting the flow. Though pullling the bag up periodically allowed it to run again each time. Worth a try though as you say, but wouldn't go too fine on the sieve mesh.

foxy · Aug 27, 2024

6Trails said:
I tried the bag outside the malt pipe once but what I found was that flour went through the plates but all gathered in the bag instead of coming back up top, ended up completely restricting the flow. Though pullling the bag up periodically allowed it to run again each time. Worth a try though as you say, but wouldn't go too fine on the sieve mesh.

That is what I envisage happening. Maybe a fine hop spider for the return pipe to flow into would be the answer.

peterpiper · Aug 28, 2024

foxy said:
A good read here. Grain crush, and going for a coarse crush leaves about 7% of the grain uncracked leading to a drop in efficiency but most programs account for this. Crushing your grain allows you to take up the slack.
https://byo.com/article/the-perfect-crush/

An important point the article notes "” It is difficult to properly mill the thins without crushing the plump portion when using just the single crush of a two-roller mill.".

The target is that different sized grains, are all milled to go give the same percentages of coarse : medium : fine : flour. A fixed gap roller mill won't do this with different grain sizes, eg if set to crush (smallish) MO correctly, typical large sized grains would be overcrushed.

TMM say they adjust crush settings, to suit each batch of grain (based on box sieve test).

peterpiper · Aug 28, 2024

6Trails said:
I'd be hitting about 78% mash eff with what I'm doing now but with none of the other hassles that come with too much grain getting through the basket. I'd say I could probably get more (I think I had about 85% on the G30) but I don't mind so long as it's predictable.
Maybe I'm not overly coarse now, it's more coarse than it was (setting 6 on the GF mill currently) but i find the conditioning leaves them more nicely cracked overall and not obliterated - lets me run the recirc near max too.

Dont mill myself.
But it does sound your coarser crush with longer mash time but fast recirc, is a more reliable bet than fine crush / possible stuck mash.

Baldylocks Brewery · Aug 29, 2024

peterpiper said:
Glad you've having success.
Was that in a BZ G4, or a GF?

23l OG 1.044, I think, would become an OG of 1.038 if diluted to 26.5l
Is coming in under gravity, an issue for you?

I finding the BZ G4 often achieves a higher OG than predicted by Brewfather.
That's been when controlling temperature using the RAPT probe (I've not yet got accurate measurements for non-RAPT).

A tall narrow profile, increases the likely temperature difference between top of malt pipe and in the base.

On a cold day, and where only slow mash recirculation is possible, the BZ G4 (neoprene jacket) can record a 10°C difference for long periods, between the built in probe and RAPT readings. Particularly noticable when doing a temperature step mash.
Which reading should be 'right'?

The 'differential override' setting, limits the base temp overshoot when using RAPT control. But the lower this setting (and the slower the recirculation), the longer it takes top of malt, to reach the desired temperature.

The balance, of fermentable to unfermentable sugars, is likely to be very different, at very different temperatures. I've had the choice: 10°C low at top (for normal period), vs 10°C high at base (for the extra 20 minutes it takes for top to reach the 'right' temperature).

I'm starting to believe, that waiting for the the top temperature to reach the required value (ie RAPT controlled), for the full time, doesn't produce the beer expected. Generally too full bodied, due to unfermentables.
For lighter style beers, I'm preferring those it produces when mashing using bottom sensor temp control (rather than RAPT). I'd like to use RAPT all the time, so maybe need to tweek the brew profile.

Hi PPP
Sorry about the pause in replying but it's been a full on week.
I'm currently G4 brewing and yes regularly coming under gravity so it's a nut I'm keen to crack.
I've seen some big differences between the onboard temp and a digi thermometer at the top of the mash so understand your comments and am going to invest in the RAPT BT one for the next brew.
Following your post and the change in the last mash I'm more confident in recirculating so will turn up the flow next time as I only ran it intermittently and slowly last time.
I'm also investing in a PH meter as I live in Kent and the water isn't great and based on the water report I've been adding lactic acid to bring the Brewfather numbers out of the red.
Thanks again for the advise.
Simon

Mr & Mrs Smith · Aug 30, 2024

peterpiper said:
He didn't mention using one!

Another Crisp article 'oats-in-brewing', covers the maths of grainbed differential pressure & compaction.

Tongue-in-cheek remark.
The emphasis on the grain bed and crush differ for those carrying out full-volume mashing. I have my Hop Cat 40 litre now and can get back in the saddle of brewing. What I have found in the past with full-volume mash is to grind the grains fine enough to establish good flow through the bed without too much flour. As I am not sparging the filter at the bottom of the tun becomes somewhat irrelevant. As long as the grains are cracked open enough, allowing the enzymes to do their work of converting the starches to sugar and the flow through to the return pipe isn't hindered.

Davegase · Aug 30, 2024

Baldylocks Brewery said:
I'm also investing in a PH meter as I live in Kent and the water isn't great and based on the water report I've been adding lactic acid to bring the Brewfather numbers out of the red.

If you're close to Canterbury there is a Spotless water station there.
I use it for the majority of my beers now.

brewsby · Aug 31, 2024

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.

Davegase · Aug 31, 2024

brewsby said:
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.

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.

ChrisD123 · Aug 31, 2024

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?

brewsby · Aug 31, 2024

ChrisD123 said:
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've just been putting the end of the silicon hose roughly at the surface of the liquid at the side of the mash pipe. I find I can achieve this by just laying the hose across the top of the lid so it enters the central hole at an angle and turning the recirc arm depending on the level of the mash. As long as the flow is reasonable and there's an inch or two of liquid over the grains this seems to keep the mash temp pretty even across the bed (I tested this today using a handheld temp probe).

Davegase · Aug 31, 2024

ChrisD123 said:
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?

Personally I've recirculated with and without the top plate without any problems.
I have also used the KegLand Sparge Sprinkler from kegland on the recirculation pipe.
The KegLand Sparge Sprinkler is a super simple device designed to help in spreading and distributing your wort in a mash tun / sparge vessel. It can also be used as the final transfer piece to assist in aerator your wort prior to pitching your yeast.

It is also designed to fit through a BrewZilla Glass or Metal Distillation lid so you can recirculate evenly over your mash by adjusting the pumps ball valve or % Pump Feature for Gen 4 users.

I've also suspended the top plate just above the mash using the lifting bar and copper wire.

ChrisD123 · Aug 31, 2024

I havent had any issues re using the top plate but am just thinking ahead so to speak....

Twostage · Aug 31, 2024

ChrisD123 said:
I havent had any issues re using the top plate but am just thinking ahead so to speak....

I used it a couple of times but it was difficult to remove if I wanted to stir the mash so I stopped using it.

I haven’t felt the need for a mid-mash stir for a while so I might try it again.

6Trails · Aug 31, 2024

It's definitely handier not having the top plate for the likes of step mashing so you can stir it, but I've never found a solution for where the Bluetooth temp probe can go without it. Might need to try rig up something.

The Baron · Aug 31, 2024

I have a home made sprinkler attached just above the wort level

ChrisD123 · Sep 1, 2024

The Baron said:
I have a home made sprinkler attached just above the wort level

Tell me more..might try that myself

The Baron · Sep 1, 2024

Quite simple but not perfect I have used the Bulb off of a turkey baster and drill some holes in it then attached to the silicon tube

ChrisD123 · Sep 1, 2024

The Baron said:
Quite simple but not perfect I have used the Bulb off of a turkey baster and drill some holes in it then attached to the silicon tube

Nice one thanks

Baldylocks Brewery · Sep 3, 2024

Davegase said:
If you're close to Canterbury there is a Spotless water station there.
I use it for the majority of my beers now.

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

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