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Brewzilla Gen4 Discussion/Tips Talk

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I am considering upgrading to the 65 from the 35L ... Anyone done this? What were the big differences?

Do you use the HED or the false bottom ... Or both.
 
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First I did some experiments while evaluating a 3-roller grain mill. I iterated through a couple different sparge processes using a 2-3 vessel system, utilizing a recirculating mash RIMS system. I did this with multiple batches of grain from the same sack to try to minimize grain variation contribution. Then I just did the mash, collected the data, and made the following tables noting the time for the "transfer time from mash end to full boil volume of wort collected".

These were done about a year apart, so the grain batches weren't the same between the 2-roller and 3-roller mill. But all of the 2-roller trials where from the same sack of grain, and all of the 3-roller trials were from its own sack of grain.

View attachment 878681
Hit 90% after doing a 4 hour floating sparge in my BZ G4 35L. After having to pause the brew day.
Don't plan on doing that regularly. But it kind of proves the point, that others have made, that remaining sugars need time to diffuse out of the larger grain particles. So the slower the sparge, and the thinner the mash increases efficiency.
 
I use the neoprene jacket, and now that the weather is cooling here, I drape a dish towel over the recirc arm to limit deltaT on arm and lid.

I find the center of the mash bed is pretty stable even with slow flow.

One option for better stability might be to divert some flow around the malt pipe, to kind of jacket the grain bed? (edit: credit bobby for this idea. He has a white paper somewhere describing his solution.)
Hey Bobbi M, I'd love to see that white paper
 
(Moved from another thread.)

Has anyone set their temperature calibration points, used their Brewzilla fine for a while, then had to reset them because the reading seemed to be off again?
 
So yesterday I got delivery of my Brewzilla 4.1 35L, and today I was testing and cleaning it, including the whirlpool arm.

And i got to wondering, why does this have a whirlpool arm? As I understand it, whirlpooling makes the trub settle into a cone in the center of the vessel, but on the Brewzilla the drain hole is in the middle, so surely whirlpooling is bad? or does the trub only form on the false bottom and not over the drain?
 
So yesterday I got delivery of my Brewzilla 4.1 35L, and today I was testing and cleaning it, including the whirlpool arm.

And i got to wondering, why does this have a whirlpool arm? As I understand it, whirlpooling makes the trub settle into a cone in the center of the vessel, but on the Brewzilla the drain hole is in the middle, so surely whirlpooling is bad? or does the trub only form on the false bottom and not over the drain?
You will want to get the HED, heat exchanger disk - that sits on the bottom above the drain hole. It disperses the heat better and makes a nice bed for the floating hops sinking after a whirlpool.

My method ... 10 min left in boil, drop in a whirlfloc tablet (or 1/2 if u like). Whirlpool begins.
Boil ends, cool down with immersion chiller and keep whirlpooling a bit. It helps cool it down faster. After about 10 minutes, turn off whirlpool and let it settle for 10 minutes or more.

Fill up your fermenters when it gets close to "cool enough" depending on your recipe and external temps.
 
I have that. OK so it doesn't cover the drain, thanks, that answers the question.
At the end... The HED will be covered in a cake of hops. It doesn't get everything, but don't sweat it. Just let those stray hop flakes go to the fermenter with the wort. It should foculate out with the "clean" yeast for your recipe.
 
I've been brewing on my BZ Gen 4 for the past 3 years now. I seem to be hitting 70% mash efficiency pretty consistently which sounds about right given the complexities and limitations of the narrow malt pipe. I incorporated using a brewing bag INSIDE the malt pipe like others which has allowed me to grind more aggressively.

One thing that's been a pain for me is stirring. I use a massive whisk. Because the malt pipe is so narrow, it's hard to really get leverage. Plus, with the bag on the inside of the malt pipe, the bag can sometimes start to twist or fall, so I have to kind of hold that up while stirring the mash.
I've been thinking about investing in a drill attachment mash stirrer like this:
1753724610580.png


https://www.morebeer.com/products/p...-powered-mash-stirrer-mixer-14-hex-drive.html

The biggest question is how do I use this in conjunction with the bag? It seems like the minute this touches the bag, it'll get all twisted up and turn into a nightmare.

Move the bag to the outside of the malt pipe? Ditch the bag altogether? I'm not necessarily looking for an improved mash efficiency - just an easier dough-in process since stirring is kind of difficult.
 
I'm fairly sure the grain basket is the same between the gen 4 and gen 4.1? if so then I say dump the bag, I don't use one with my 4.1 and I had no problems with grain escaping the basket, even with a very fine mill, even when I'm pressing doughballs against the side/bottom of the basket to break them up.

I've not used a whisk, as I got a brewzilla bundle with their mash paddle included, and that does the job just fine. I wonder about you saying it's a 'massive' whisk, if it's too large then that's going to make it much harder to stir with it as it's trying to move more of the mash - you only need to be able to reach the bottom of the basket and it's really not that big, the paddle area on the one brewzilla make is really very small, and as a result it moves pretty effortlessly through the mash - how thick is your mash, typically? are we talking a typical mash of say 11lb of grain for a 5 gallon batch, or higher than that?
 
Yeah, I'm really leaning towards dumping the bag. I only ever brewed without the bag on my FIRST batch. I stirred too aggressively and punched out the bottom of the malt pipe while doing so which dumped a bunch of grain into the second false bottom and clogged my pump. DEFINITELY a lot of user error there, but I picked up a bag and never stopped to reconsider if I even really need a bag.

I might do a little trial run without the bag on my next batch to see how I do. I condition my grain and crush it to credit card thickness. It's not like I'm grinding SUPER fine or anything.

Plus, everyone says using a bag provides easier cleanup, but I beg to differ. Washing the bag is a total pain in the butt. Plus you still have to rinse and wash the malt pipe anyways. It's really more to clean, but it does provide a nice little bit of insurance to avoid any grain getting clogged in the pump.

As for my whisk - it's one of those large French whisks that everyone uses. It's maybe 18" and does a good job of breaking up dough balls. Just a little awkward to use in such a narrow malt pipe.

I've always gone for a more wet mash. I believe I'm doing 1.66qt/lb. Also, most of my recipes are 12-13lb (not including rice hulls) which is probably pushing the rig to the limit.
 
Plus, everyone says using a bag provides easier cleanup, but I beg to differ. Washing the bag is a total pain in the butt.
I'm not trying to encourage you to keep using the bag. I'm just wondering... If you were to turn the bag inside out and shake the grains out, then let it dry, I would think that after it's dry it should be easy to get the rest off with another good shake or maybe brushing it off.

I'm assuming that your pain is with getting all the grain matter out.
 
I'm not trying to encourage you to keep using the bag. I'm just wondering... If you were to turn the bag inside out and shake the grains out, then let it dry, I would think that after it's dry it should be easy to get the rest off with another good shake or maybe brushing it off.

I'm assuming that your pain is with getting all the grain matter out.
You're right. I'm a stickler about cleaning. I usually turn it inside out, bunch it up with some soap and then rinse it out while brushing grain/husks away. I rinse probably 98% of the material off it. Then I place it over my malt pipe in my drying area and then shake it out once completely dry. It's not terrible, but I just don't like dealing with it.
 
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Plus, everyone says using a bag provides easier cleanup, but I beg to differ. Washing the bag is a total pain in the butt. Plus you still have to rinse and wash the malt pipe anyways. It's really more to clean, but it does provide a nice little bit of insurance to avoid any grain getting clogged in the pump.
I also had a problem clogging the pump the first time with the BZ gen 4... I use a grain bag OUTSIDE the grain tube... there is no problem with dirt in the bag.
 
^ That's what I do as well. BIAB bag outside the malt pipe. I had tried it inside the malt pipe but found that outside works easier and no snags when stirring the mash with your implement of choice. Probably not needed for all brews but it's peace of mind of knowing there will be no clogged pump and cleaning the bag takes all of 5 min
 
You're right. I'm a stickler about cleaning. I usually turn it inside out, bunch it up with some soap and then rinse it out while brushing grain/husks away. I rinse probably 98% of the material off it. Then I place it over my malt pipe in my drying area and then shake it out once completely dry. It's not terrible, but I just don't like dealing with it.
Hop bags I give a good rinse to and then put them in the washing machine inside out.
Before use a good rinse and or starsan/ boil. Not noticed any contamination issues.
 
I've been brewing on my BZ Gen 4 for the past 3 years now. I seem to be hitting 70% mash efficiency pretty consistently which sounds about right given the complexities and limitations of the narrow malt pipe. I incorporated using a brewing bag INSIDE the malt pipe like others which has allowed me to grind more aggressively.

One thing that's been a pain for me is stirring. I use a massive whisk. Because the malt pipe is so narrow, it's hard to really get leverage. Plus, with the bag on the inside of the malt pipe, the bag can sometimes start to twist or fall, so I have to kind of hold that up while stirring the mash.
I've been thinking about investing in a drill attachment mash stirrer like this:
View attachment 880994

https://www.morebeer.com/products/p...-powered-mash-stirrer-mixer-14-hex-drive.html

The biggest question is how do I use this in conjunction with the bag? It seems like the minute this touches the bag, it'll get all twisted up and turn into a nightmare.

Move the bag to the outside of the malt pipe? Ditch the bag altogether? I'm not necessarily looking for an improved mash efficiency - just an easier dough-in process since stirring is kind of difficult.
A minimal stir regime, has done wonders to my BZ g4 performance.

After 4 hard work brews, with lots of power stirring. With the last, a Hefeweizen, ending up with a thick layer of burnt flour on the base, and an overheat shutdown (it ended smokey and undrinkable), I ordered bags.

But in the meantime, found the Graham Wheeler advice:
* Minimal stirring at dough in (just enough to break up any dough balls, without knocking off trapoed air, which increases grain buoyanccy giving a more open grain bed); 15min grain bed rest (grain hydrates expands and interlocks) before any recirculation;
* Never stir again (which will destroy the grain bed filter).
Also (from Bairds Malts):
* Limit recirc flow to prevent large wort level rise, that could result in a compacted grain bed (giving slow recirculation, or a stuck mash). I aim for max 20mm rise.

40 happy brews since, and the bags have never been needed!
 
My sample size is a fraction of yours, at only 1 single brew compared to your 40, but I suspect that the largest contribution is the low recirc flow, I also did a very slow recirc, based on what I had read in several places (using the valve to control it, not the pump strength), to the point that the wort was slowly dribbling out of the pipe. I was stirring every 15 minutes.

If you think about it, the recirc pump is forcefully pumping the wort out from the bottom, which at high 'speed' is going to create a suction force pulling down, which could cause the compacted grain bed, rather than it being caused by a wort level rise.

Another point of possible comparison is using the top grain cover vs not using it. I didn't use it, because I realised at the last moment that I had messed up and put a handle through the hole that's intended for you to put the temp probe through, AND I'd read in a few places not to use it so I was 50/50 anyway, but kegland themselves are really very insistent that you should use it, and that it greatly improves recirculation.
 
My sample size is a fraction of yours, at only 1 single brew compared to your 40, but I suspect that the largest contribution is the low recirc flow, I also did a very slow recirc, based on what I had read in several places (using the valve to control it, not the pump strength), to the point that the wort was slowly dribbling out of the pipe. I was stirring every 15 minutes.

If you think about it, the recirc pump is forcefully pumping the wort out from the bottom, which at high 'speed' is going to create a suction force pulling down, which could cause the compacted grain bed, rather than it being caused by a wort level rise.

Another point of possible comparison is using the top grain cover vs not using it. I didn't use it, because I realised at the last moment that I had messed up and put a handle through the hole that's intended for you to put the temp probe through, AND I'd read in a few places not to use it so I was 50/50 anyway, but kegland themselves are really very insistent that you should use it, and that it greatly improves recirculation.
I never use the top plate during mash, to avoid extra weight on grain bed.
As I go for a fairly thin mash, the malt is always covered with a layer of wort. Which is going to evenly spread recirculation anyway.
I do use it for sparging.

Can't work out why people would want to stir during mash.
I did stir, after getting a stuck mash, on first few brews in BZ. But still could only manage a slow recirculation rate.

Malt is a mixture of coarse and fine particles, and flour. Stirring frees the flour from the grain bed filter. At a slow flow rate, a lot of flour will settle out on the base, rather than be recirculated.
 
I never use the top plate during mash, to avoid extra weight on grain bed.
As I go for a fairly thin mash, the malt is always covered with a layer of wort. Which is going to evenly spread recirculation anyway.
I do use it for sparging.

Can't work out why people would want to stir during mash.
I did stir, after getting a stuck mash, on first few brews in BZ. But still could only manage a slow recirculation rate.

Malt is a mixture of coarse and fine particles, and flour. Stirring frees the flour from the grain bed filter. At a slow flow rate, a lot of flour will settle out on the base, rather than be recirculated.
To get rid of the dust...flour...dry mix the grains in a bucket...then gradually add them to the basket...the dust will be underneath the bucket...then lift and hit the basket well on a table...the dust will come out from underneath and you will be free of them...slowly place the basket in the pan with water...stir slowly...let it rest for 15 minutes and turn on the pump ...low flow
 
Can I ask, is the ball valve tap on the bottom loose for anyone else? Mine 'works' fine, there's no leak or anything, but it isn't bolted tight to the body and is loose and rattley. I can't see any other way to interpret the installation instructions, but the nut that goes on the inside just doesn't tighten all the way to the body of the kettle, the thread stops short, so the tap ends up having a lot of play - I just want to know if that's 'normal' or if mine has a fault that that nut can't be tightened more.
 
I can't right now, my wife is currently still in bed after a night shift at work and my kit is all stored in a room directly behind the bed, but I've been looking again at the installation instructions and I think mine might have a manufacturing issue, although I can't imagine how it could have possibly happened.

Untitled.png


This is from the tap installation instructions at https://docs.rapt.io/equipment/rapt-brewzilla/setup-and-assembly

You see between the wall of the kettle and the bolt there is a raised area of the kettle wall, that the nut tightens against? Well I'm pretty sure mine doesn't have that raised area., meaning my bolt has to tighten against the main kettle wall but the thread of the bolt doesn't go that far.

I can't check for sure until SWMBO wakes up, but I'm pretty sure that's my problem. Huh, how the hell did that happen.

If that's it, then I have to decide whether to return it as faulty, or just add myself a plastic or silicon washer there to replace it.
 
I can't right now, my wife is currently still in bed after a night shift at work and my kit is all stored in a room directly behind the bed, but I've been looking again at the installation instructions and I think mine might have a manufacturing issue, although I can't imagine how it could have possibly happened.

View attachment 883742

This is from the tap installation instructions at https://docs.rapt.io/equipment/rapt-brewzilla/setup-and-assembly

You see between the wall of the kettle and the bolt there is a raised area of the kettle wall, that the nut tightens against? Well I'm pretty sure mine doesn't have that raised area., meaning my bolt has to tighten against the main kettle wall but the thread of the bolt doesn't go that far.

I can't check for sure until SWMBO wakes up, but I'm pretty sure that's my problem. Huh, how the hell did that happen.

If that's it, then I have to decide whether to return it as faulty, or just add myself a plastic or silicon washer there to replace it.
It does sound like it's a manufacturing issue, but it's not a big deal. I would get a washer or two and put it in there. Maybe send the info to Kegland so they can check on their design.
 
I can't right now, my wife is currently still in bed after a night shift at work and my kit is all stored in a room directly behind the bed, but I've been looking again at the installation instructions and I think mine might have a manufacturing issue, although I can't imagine how it could have possibly happened.

View attachment 883742

This is from the tap installation instructions at https://docs.rapt.io/equipment/rapt-brewzilla/setup-and-assembly

You see between the wall of the kettle and the bolt there is a raised area of the kettle wall, that the nut tightens against? Well I'm pretty sure mine doesn't have that raised area., meaning my bolt has to tighten against the main kettle wall but the thread of the bolt doesn't go that far.

I can't check for sure until SWMBO wakes up, but I'm pretty sure that's my problem. Huh, how the hell did that happen.

If that's it, then I have to decide whether to return it as faulty, or just add myself a plastic or silicon washer there to replace it.

@Zadkiel I just checked mine and can confirm it also has that raised/flanged part on the wall. The nut sits against it exactly as in your photo, and it's very solid - I haven't had to adjust or play with it since initial assembly. Probably a silly question as this is the thread for the Gen 4 - but is yours Gen 4?

Either way, if yours does indeed have the raised/flange - maybe the nut has cross threaded? If not, as you've suggested a simple silicon washer will probably do the fix, although if it's easy enough to return i'd probably do that.

Cheers!
 
it's gen 4.1 - I'd also considered the possibility that I'd misremembered about the existence of that raised area and instead it's the thread on the nut or bolt. I'll be able to check later.
 
If that bit was indented it wouldn't make the kettle wall any thicker it just allows the nut to tighten onto a flat surface, could be the tap hasn't enough thread cut on it to tighten it.
Luckily it's not a sealing join, on the guten and earlier brewzillas, robobrews the tap opened into the kettle so had to be a watertight union with washer, nut and tap.
As mentioned though a further washer should allow you to get it tight.
 
Can I ask, is the ball valve tap on the bottom loose for anyone else? Mine 'works' fine, there's no leak or anything, but it isn't bolted tight to the body and is loose and rattley. I can't see any other way to interpret the installation instructions, but the nut that goes on the inside just doesn't tighten all the way to the body of the kettle, the thread stops short, so the tap ends up having a lot of play - I just want to know if that's 'normal' or if mine has a fault that that nut can't be tightened more.

Mine is super loose. Doesn't leak. It's a Gen 4, purchased in May 2025.
 
Mine is super loose. Doesn't leak. It's a Gen 4, purchased in May 2025.
That's not surprising given that the leak point would be where the hose attaches to the tailpiece of the tap. The kettle attachment of the tap doesn't have to seal anything. But must be irritating with that wobbliness.
 
Update: So I was kinda wrong about the raised part being missing. it is there, just a lot less pronounced than it was in the picture - the issue was just that the bolt was really hard to tighten to the body, and I guess when I was putting it together I gave up on it. The bolt is huge, I didn't have any spanner that would fit it, even my mulgrips and my adjustable spanner were too small, and for some reason you can't tighten it beyond a certain point by hand. Also one of the 'feet' of the unit gets in the way. Eventually after quite a bit of struggle I was able to use a pair of pliers to get it mostly tight, it no longer wobbles/rattles but it does still spin round (I mean the tap rotates against the body, like a plastic tap on a plastic bucket fermenter does), I'd need more tightening than a pair of pliers can do on a huge nut like that in order to stop the spin.
 
That's not surprising given that the leak point would be where the hose attaches to the tailpiece of the tap. The kettle attachment of the tap doesn't have to seal anything. But must be irritating with that wobbliness.

It is- but I only drain it at the very end and it fills a small cup so I'm not really that annoyed by it!
 
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