Grain Mill recommendations and grain crush for Brewzilla Gen4

[peterpiper]

Yes that's it, with the original pump configuration.

The silicon tube I'd ordered was 10mm / 16mm (recirculation arm silicone is 10mm / 13.5mm). The new one just fits the lift holes, but is too large to slide in, to make it secure.
So I always use the original hose for outer recirculation, and the new one via the malt.

I keep a length of double sided velcro (50mm x 200mm) wrapped around top of sparge arm, so the loose end can secure the new pipe (and adjust the height).
Height control is much easier than with the old one.

I put pipe down the lift hole, I've aligned with the recirculation arm side.
This gives most flow, down the side where the heaters are.
TheBaron uses flow down the opposite side (where the temp sensor is). As I always use RAPT, for main temp control, accurate internal sensor reading, seems less important than having settled flour burn on the heater.

It looks like the overall flow was limited more by pipe size, rather than the pump. So watching maximum flow coming from both pipes, if you completely close, then re-open, either valve, the flow from the other pipe hardly changes.
The total max flow with both pipes, appears much higher. Will try to remember to measure it, on next brew day.

While heating to strike temp, recirc via malt pipe (using recirc arm).
Once strike temp reached, start recirc outside malt pipe at max rate. This initially flushes out any cool water there.

Gradually stir in grain very gently. To just break up lumps, without knocking off attached air bubbles (more buoyant grain = less compact grain bed).
Continue max outer recirc, with lid on, during 15-20min grain bed rest (while grain & flour hydrate). This prevents most cooling you otherwise get during the rest.

Maintaining outer recirc, do 10 min of slow recirc via grain. Then gradually increase grain recirc, till wort level starts to rise (by maximum of around 10mm). Too much rise can compact the grain bed (with the differential pressure).
I position 2nd pipe 10mm over liquid level (after hydration / rest, is complete), to act as a guide.
Check grain max recirc later, & after any temperature steps.

If you ever need to blow back through recirc pipe, to clear a blockage, you'd obviously need to close valve on the other pipe, for this to work.
It might be worth doing a blow back, at end of mashout, to clear any stuck grain or flour. Then recirc at max rate for a minute or two, via grain bed only, so any freed particles get filtered out (rather remaining in the boil).

If using the new pipe for final pump out, be sure to recirc through it during the boil.
With a 2m length, it can fill fermenters on my workbench (which the original pipe wouldn't reach).

Otherwise, to empty new hose, for disconnection. I hold end in a cup, while lowering, till pipe flat on floor, and unscrewed.

My BZ is on a wheeled base, that gives drain tap an extra 90mm ground clearance. This makes getting the screw connector on & off easier.
It's also in a large plant saucer, to catch drips.

I measured BZ G4 35L, pump flow today. Via original recirc arm & hose, and via the second recirculation hose added (a 10mm internal dia. hose from drain tap).
I only measured times to fill a 1L container, so figures very approximate, but still give an idea of the flow.

Time to fill a 1L container (container on bench, at height of sparge arm top; from prefilled pipe; 5L in BZ):

Via original recirc arm, fully open (drain closed): 18sec (0.056 L/sec).
Via original recirc arm, fully open (drain recirculation fully open): 28sec (0.034 L/sec).
Via second recirculation hose, fully open (original recirc closed): 8sec (0.125 L/sec).
Via second recirculation hose, fully open (original recirc fully open): 10sec (0.1 L/sec).

So recirculation via the drain tap, is quite a bit faster. Despite using same internal diameter hose, as the original flexi hose.
So there must be some restriction, in part of the original recirculation fixed pipework. I'd guess that it's not a full bore valve (but that the drain tap is).

If doing pumped transfer to fermenter, a pipe from drain tap spigot would save time. 23L in just over 3 minutes, versus nearly 7 minutes via recirc arm.

 

[RoomWithABrew]

Flow increases by the 4th power of the radius in a pipe.
So eliminating narrowing in the pipework makes a big difference.

 

[peterpiper]

Did that Foxy 20ltrs in a 20 ltr brew so only 5 litres left to sparge and stirred loads of times but it still kept building up and the bottom emptying. All fully insulated with the Brewzilla jacket and pipe cover.https://crispmalt.com/en-us/news/how-to-use-oats-in-brewing/

Just trying to get my head around it so seeing how much flow I can get with less flour in it.
I could add Oat husks but the grainbill is simple just 3100g od Pilsner and 250 of Torrified Wheat and as I added 200g of them to the last brew it did not do the trick still had to keep stirring to release the water back to the bottom reservoir several times
Ps the last brew was not a over large grainbill but it was a porter with plenty of adjuncts, crystal etc with a low DP of 34 so that may not have helped

Increasing the reservoir (lifting the malt pipe) won't solve the problem, just delay its appearance. This can make matters worse.

A difference in liquid levels, between that inside the malt pipe and that outside, gives a differential pressure.
Where the levels are the same, it is a floating mash (no pressure on the grain bed).
But as difference between levels increases, more weight is taken by the grain bed, the differential pressure compresses the grain bed, restricting the flow, increasing the level difference......! Ultimately when there's no liquid left under the malt pipe, the base of the grain bed is supporting total weight of grain and water above. This leads to a compacted bed, which doesn't drain.

Oats in brewing this article from Crispmalt, discusses bed compression and differential pressure.


I started with BZ4, doing a vigorous stir at dough in, using a spiral drill mixer. But often got slow draining, or stuck, mash, needing lots of subsequent stirring.
Worst brew was a Weisenbock, 6.5kg grain 50% being wheat, that needed stirring multiple times. This stopped the grain bed being a filter, so lots of flour fell through and settled on base, this then burnt during boil. I had an overheat shutdown for a while (around 120°C), and ended up with 6mm of burnt black crust.
Beer tasted extremely smokey.

But all going much better, since finding Graham Wheeler's suggested method (British Real Ale 3rd ed), of minimal stirring at dough in, just enough to break up lumps.
The idea is to avoid knocking off, any air attached to the grain, as attached air increases buoyancy and forms a more open bed.
Never stir the mash after this, and don't put on the top plate (until squeezing dry, after sparge).

After dough in, leave a 15 - 20 minute grain bed rest period, for the grain and flour to hydrate, before starting slow recirculation through the grain.
I imagine that once hydrated, each grain will have expanded, so making a firmer filter matrix.
After 10 min, throttle for max flow, without level rising any more than 10mm.

Doing recipes with 50% wheat, or 25% rye, I still never achieve 100% recirculation. A 25 or 30% flow might work slower, but it's easier than having to sort a stuck mash.

For step mashes, I try to get most of each step, from gradual additions of boiling water (without stirring).
I'm just wondering, if slow water additions could be better done from a boiler, via my hose on the drain tap?

 

[The Baron]

I have sussed most of it PP I do minimal stirring when doughing in then let the bed settle/rest for 10 minutes or so with no recirculation over the bed but down the side of the maltpipe near the bottom temp probe so as to keep the temp as close as possible(I am using the additional Rapt temp probe) and this does seem to have sorted most of the problems.
I avoid turning down the re-circ flow as this then adds to overshoots as the flow is needed to keep pumping up the hotter wort from the bottom and if not done quick enough this temp builds up compared to the mash temp so it does really in a ideal world need full flow for a consistent mash IMO. I also turn the heat % down to 30/35% to help this too once in the mash.

 

[Frisp]

Yes that's it, with the original pump configuration.

The silicon tube I'd ordered was 10mm / 16mm (recirculation arm silicone is 10mm / 13.5mm). The new one just fits the lift holes, but is too large to slide in, to make it secure.
So I always use the original hose for outer recirculation, and the new one via the malt.

I keep a length of double sided velcro (50mm x 200mm) wrapped around top of sparge arm, so the loose end can secure the new pipe (and adjust the height).
Height control is much easier than with the old one.

I put pipe down the lift hole, I've aligned with the recirculation arm side.
This gives most flow, down the side where the heaters are.
TheBaron uses flow down the opposite side (where the temp sensor is). As I always use RAPT, for main temp control, accurate internal sensor reading, seems less important than having settled flour burn on the heater.

It looks like the overall flow was limited more by pipe size, rather than the pump. So watching maximum flow coming from both pipes, if you completely close, then re-open, either valve, the flow from the other pipe hardly changes.
The total max flow with both pipes, appears much higher. Will try to remember to measure it, on next brew day.

While heating to strike temp, recirc via malt pipe (using recirc arm).
Once strike temp reached, start recirc outside malt pipe at max rate. This initially flushes out any cool water there.

Gradually stir in grain very gently. To just break up lumps, without knocking off attached air bubbles (more buoyant grain = less compact grain bed).
Continue max outer recirc, with lid on, during 15-20min grain bed rest (while grain & flour hydrate). This prevents most cooling you otherwise get during the rest.

Maintaining outer recirc, do 10 min of slow recirc via grain. Then gradually increase grain recirc, till wort level starts to rise (by maximum of around 10mm). Too much rise can compact the grain bed (with the differential pressure).
I position 2nd pipe 10mm over liquid level (after hydration / rest, is complete), to act as a guide.
Check grain max recirc later, & after any temperature steps.

If you ever need to blow back through recirc pipe, to clear a blockage, you'd obviously need to close valve on the other pipe, for this to work.
It might be worth doing a blow back, at end of mashout, to clear any stuck grain or flour. Then recirc at max rate for a minute or two, via grain bed only, so any freed particles get filtered out (rather remaining in the boil).

If using the new pipe for final pump out, be sure to recirc through it during the boil.
With a 2m length, it can fill fermenters on my workbench (which the original pipe wouldn't reach).

Otherwise, to empty new hose, for disconnection. I hold end in a cup, while lowering, till pipe flat on floor, and unscrewed.

My BZ is on a wheeled base, that gives drain tap an extra 90mm ground clearance. This makes getting the screw connector on & off easier.
It's also in a large plant saucer, to catch drips.

PP that is exactly what I was after , thanks.

 

[The Baron]

PP that is exactly what I was after , thanks.

I will give that a try PP, sounds pretty good to me and as you said if you have flow to the bottom as well as going through the mash should solve the starvation of the bottom reservoir.
Need to order some silicon tube how much did you order and where from?
Edit
Silicon ordered 2mtrs
I will need to change the pump plumbing back to factory setting as well

 

[peterpiper]

I will give that a try PP, sounds pretty good to me and as you said if you have flow to the bottom as well as going through the mash should solve the starvation of the bottom reservoir.
Need to order some silicon tube how much did you order and where from?
Edit
Silicon ordered 2mtrs
I will need to change the pump plumbing back to factory setting as well

Outer flow, helps maintain core temperature during grain bed rest, and speeds up any temperature steps (as it gets rid of the surrounding, cool water, sitting at previous step temp).
It can also improve mash efficiency, as the surrounding water / deadspace, becomes part of the the mash water (making it more dilute). Otherwise this deadspace water is mostly unused, until the malt pipe is lifted.

I also ordered a 2m length (of platinum cured). It's a bit longer than what's needed for recirc, but the extra length is handy during pump out.

A stainless steel hose clamp, makes sure the hose can't accidentally come off the drain spigot. Any type would do, I just happened to have some left over, stainless ones.
I'd thought of changing the drain hose connector, to a quick release type (as fitted on recirc arm). But the screw on spigot connector, has been easy enough (over 6 brews so far) for connecting once on, and once off (for final cleaning drain) per brew.

 

[peterpiper]

.. (I am using the additional Rapt temp probe) and this does seem to have sorted most of the problems.... I avoid turning down the re-circ flow as this then adds to overshoots as the flow is needed to keep pumping up the hotter wort from the bottom and if not done quick enough this temp builds up compared to the mash temp so it does really in a ideal world need full flow for a consistent mash IMO. I also turn the heat % down to 30/35% to help this too once in the mash.

As the discepancy, between Rapt probe readings, and the built in sensor, is often so large. I'm surprised, that brewers can be getting consistant results.

I often wonder, if the various (historical) recommended mashing temperatures, would be the same if they'd had systems with Bluetooth probes, to record the real grainbed temperature.
When working from RAPT sensor, I now aim for the lower end, of the recommended temperature range.

I still think, there should be a BZ G4 guide / tips sticky thread.

 

[foxy]

It can also improve mash efficiency, as the surrounding water / deadspace, becomes part of the the mash water (making it more dilute). Otherwise this deadspace water is mostly unused, until the malt pipe is lifted.

How can it improve mash efficiency? The sparge water will dilute the mash, why is it so important to worry about whether the dead space liquor around the side of the grain basket is being used?

 

[RoomWithABrew]

I think the mash temperatures are based on the enzyme performance, not a guess as to how a million different mash tuns would work!

Consistency has little relation to accuracy, especially if you've seen me slice a golf ball.

 

[peterpiper]

How can it improve mash efficiency? The sparge water will dilute the mash, why is it so important to worry about whether the dead space liquor around the side of the grain basket is being used?

If you're getting the efficiency you're after, there's no need to worry.

I don't know all the complexities of mash extraction efficiency.
Sometimes a thicker mash, with higher enzyme levels can help. But whatever the initial mash thickness, a thinner final mash should help efficiency.

When you soak, say crystal malt grain in water, over time the sugar concentration in the wort will approach that left in the grain. Hopefully after a 60 or 90 minute mash the concentrations would be equal.
Similar, but more complex, with the other mated grains where enzymes are at work.

Where say 5% of mash water is unused. At end of mashing the final balanced concentrations, would have a higher wort SG, with correspondingly higher levels of sugar in the grain.
When the malt pipe is lifted, the wort is simply diluted by any completely unused water.

Sparge water gradually flushes off wort clinging to the grain, and rinses off surface sugars.
But I can't see a normal sparge, rinsing much sugar from within the grain. So id expect the additional sugar, left in the grain from having underutilised mash water (or from thicker mashes), would mostly remain behind.

A 60 minute sparge, maybe, would extract them.

It would be interesting to see if anyone's tried doing test mashes, on leftover grain. Measuring the sugar extracted, to compare original (thin vs thick mash) efficiency.

 

[Agentgonzo]

I keep on meaning to take a known quantity (say half a kilo) of spent grain from the mash and put it into a large amount (say 5L) of water and leave it overnight and after 2 regularly to see how much extra sugar it'll extract. My guess is a fair amount. But I keep forgetting with the other things going on during the brewday.

The other thing I keep thinking about is that extracted sugar does not necessarily equal extracted malt flavour. It's been postulated on here a few times (but never measured/experimented) that a lower efficiency ends up with more malt being put into the grist to account to compensate, which might end up with more flavour being extracted and ending up in the final beer.

 

[The Baron]

I have no proof of what you are saying Agent but I think you may be right that it would mainly extract sugars and not add to the malty taste and we know what people think of adding too much sugar to beers by some.
Ps if we are correct surely it would thin the beer out and be detrimental on some styles if over extraction occurs

 

[Jiffy176]

just out of interest, does the pump need to be repositioned, I've plumbed mine up so it is T'd off rather than being direct from the bottom of the kettle.
If using the the tap as we'll as the internal circulation I'd imagine either tap would be used to manage the flow.
Time for a play.

 

[Jiffy176]

just out of interest, does the pump need to be repositioned, I've plumbed mine up so it is T'd off rather than being direct from the bottom of the kettle.
If using the the tap as we'll as the internal circulation I'd imagine either tap would be used to manage the flow.
Time for a play.

Right confirmed this doesn't work with the pump in alternate config

 

[Jiffy176]

Right confirmed this doesn't work with the pump in alternate config

So I have just tried the config with a splitter and I managed from a pump off ball valve closed start open for 30 seconds and then close.
I measured between 3500ml and 3300ml. Taking a mean 3400ml I reckon this works out 113ml per second.
So it looks like the single exit from the recirc arm is what causes the restriction.
Will try this on my next brew but I'd easily expect full power pump from the out.

 

[foxy]

I don't know all the complexities of mash extraction efficiency.
Sometimes a thicker mash, with higher enzyme levels can help. But whatever the initial mash thickness, a thinner final mash should help efficiency.

Sparge water gradually flushes off wort clinging to the grain, and rinses off surface sugars.
But I can't see a normal sparge, rinsing much sugar from within the grain. So id expect the additional sugar, left in the grain from having underutilised mash water (or from thicker mashes), would mostly remain behind.

A 60 minute sparge, maybe, would extract them.

It would be interesting to see if anyone's tried doing test mashes, on leftover grain. Measuring the sugar extracted, to compare original (thin vs thick mash) efficiency.

I think for anyone who is worried about dead space liquor between the mash tun and the grain basket the simple solution would be to raise the basket 3 or 4 times during the mash.

A thinner mash will achieve a better conversion efficiency, as will a finer grind making sure all the starches are accessible. It wouldn't be beyond belief that maybe 10% of milled grain doesn't even get cracked open.

Sparge water does rinse off surface sugars but sparging cannot flush out sugars locked in the soaked grain. Only putting the grain under pressure to squeeze out all the excess liquid will remove the trapped sugar. When commercial breweries squeeze the grain it is left with barely any trace of moisture.

 

[peterpiper]

I keep on meaning to take a known quantity (say half a kilo) of spent grain from the mash and put it into a large amount (say 5L) of water and leave it overnight and after 2 regularly to see how much extra sugar it'll extract. My guess is a fair amount. But I keep forgetting with the other things going on during the brewday.

The other thing I keep thinking about is that extracted sugar does not necessarily equal extracted malt flavour. It's been postulated on here a few times (but never measured/experimented) that a lower efficiency ends up with more malt being put into the grist to account to compensate, which might end up with more flavour being extracted and ending up in the final beer.

The spent grain, if tasted and chewed, does seem to have slight flavour and sweetness. But it's probably not much, birds hardly touch the stuff, if it's left out.

Results of your experiment, checking for sugar and flavour, could be interesting.
Might need a fair acid addition, as there's unlikely to be enough acidity from the spent grain. Otherwise increased levels of tannin extracted, from a high PH, might mask any flavour.

It would be tricky working out the dry grain equivalent weight, in the 0.5kg of wet spent grain.
For ease, I'd maybe put the lot back (still in malt pipe), into acidified cold water. With a few litres less water, than the initial mash. And maybe recirculate, for a while, before draining.

If the result tastes nice enough, it could become the mash water for tomorrow's batch.

 

[peterpiper]

I think for anyone who is worried about dead space liquor between the mash tun and the grain basket the simple solution would be to raise the basket 3 or 4 times during the mash.

Yes, that would work if you're feeling fit.

I'd worry about causing grain bed compaction, then getting a struck mash. Especially with large grain bills, or wheat beers.
Once the grains aren't floating, the base layer of grain takes most of weight, from all the wet grain and wort above.
Thats why places use a floating sparge, to give the best flow rates.

QUOTE="foxy, post: 1268918, member: 8942"]
A thinner mash will achieve a better conversion efficiency, .......
[/QUOTE]
Brewfather, default setting for BZ4-35. Gives water volumes that seem to me, on low side for mash water, and the high side for sparge.
I usually change the ratio, upping the mash water by a few litres. Then get the desired efficiency, or better.

 

[RoomWithABrew]

I wouldn't raise the malt pipe up and down, chance the bottom plate will get raised by the liquid in kettle and grain will escape.