Good grain crush??

[RonnieBiggs]

Hi all, doing my first all grain brew in a long time. Long story short, i had sold alot of my gear a few years ago but have recently had the itch to resume brewing. In amassing things, as I do, I picked up a grain mill and have crushed the grain tonight for brewday tomorrow. I brew on a Braumeister and had my crush dialled in pretty well previously, good efficiency and never had any wort fountains. The only thing is i never took notes on my crush size. I've set the mill to a snug 1.1mm (0.043 inch). Looking at the crush and curiously wondering what your guys thoughs are?

 

[dmtaylor]

It looks pretty good. Looks a lot tighter than 0.043, which is good because I was going to tell you to aim for about 0.030 anyway.

 

[RonnieBiggs]

Yeah I did wonder if I snugged it a bit tight on the feller guage, it was a tight pull

 

[Snuffy]

Let's BREW!

 

[hungupdown]

Most husks look broken.

Braumeister recommends 1.6mm. But says that "If whole grains do not break when pressed on (with thumbnail), they were crushed too coarsely."
The supplier I use, TMM, also says that the ideal crush for AIO systems: leaves as many husks intact as possible, without leaving any whole grains that don't break when pressed..

I dont have the system, but heard that too fine a crush can lead to channeling, that can cause "fountains".

 

[RonnieBiggs]

Just finishing up the boil now
Can confirm no wort fountains, though maybe a slight pump blockage during mash out. Definitely crushed a little finer than suits my eye for the braumeister, will adjust the mill accordingly.Will report back with info on if I hit my og or not

 

[Pennine]

I brew with a braumeister too, it's pretty forgiving if you give it a few stirs throughout the mash. I still condition my malt before milling and seem to get a better crush. I also mill twice, the largest opening first and then the smallest the second pass. This really seems to help braumeister flow and always keeps me in the 80%+ efficiency range. Which is important as the malt pipe can be restrictive for some beers.

 

[RonnieBiggs]

Ended up with just under 20 litres (5.28 gallons) into the fermenter.
Grain bill was;
4.5 kg pale ale malt (9 lb 14 oz)
.4kg medium crystal (14 oz)
Measured OG 1.057

 

[RonnieBiggs]

Just finishing up the boil now
Can confirm no wort fountains, though maybe a slight pump blockage during mash out. Definitely crushed a little finer than suits my eye for the braumeister, will adjust the mill accordingly.Will report back with info on if I hit my og or not

Definitely had some issues during the 10 minute mash out after the pump had work flawlessly during the mash. Mashed out at 78c (172 f) for 10 minutes. Omce the mash out temperature was reached the pump started making excessive noise and a bit of vibration as well as stopped pumping wort through the malt pipe. I had to increase the pump speed to maximum to get the wort flowing through the malt pipe again, but the noise and vibration remained.
After removing the malt pipe and sparging, plis during clean up the pump seemed to run OK again. Didnt find anything during transfering to fermenter or on clean up that i thought would cause a blockage. Hopefully a one off. Video attached of the noise

 

[dmtaylor]

Yeah... sorry... I don't use a robot. Robots might benefit from a lesser crush I guess. Maybe now you know the limit of your system, and can just dial down on the crush an eensie notch to get it just right.

 

[doug293cz]

I suspect that your pump may have started cavitating at the higher temp of mash-out. The vapor pressure of water increases at higher temps, The pump creates a low pressure zone at its inlet, If you reach a point where the pressure at the pump inlet is lower than the vapor pressure of the wort, the wort can start boiling inside the pump, and the pump is sucking water vapor rather than liquid wort. (This is a simplified explanation, but it should give you the gist.)

Mashing out at a slightly lower temperature might be enough to eliminate the cavitation, but you may need to resort to other measures such as reducing the flow resistance of the grain bed (a coarser crush is one way to do this.)

Brew on

 

[RonnieBiggs]

Yeah... sorry... I don't use a robot. Robots might benefit from a lesser crush I guess. Maybe now you know the limit of your system, and can just dial down on the crush an eensie notch to get it just right.

Yeah I've started there by adjusting my mill gap a little larger, ill see how that goes.
I used to be a 3v guy myself but must say that an all in one system is not so much easier, a little more convenient for me though, definitely more compact and allows me to not take up the kitchen and stove are during the morning when I like to brew and the family likes to eat

 

[RonnieBiggs]

I suspect that your pump may have started cavitating at the higher temp of mash-out. The vapor pressure of water increases at higher temps, The pump creates a low pressure zone at its inlet, If you reach a point where the pressure at the pump inlet is lower than the vapor pressure of the wort, the wort can start boiling inside the pump, and the pump is sucking water vapor rather than liquid wort. (This is a simplified explanation, but it should give you the gist.)

Mashing out at a slightly lower temperature might be enough to eliminate the cavitation, but you may need to resort to other measures such as reducing the flow resistance of the grain bed (a coarser crush is one way to do this.)

Brew on

It does sound like cavitation I think?
Already opened the gap a bit and will see how that goes next time. Was coincidently weird that it happened almost the exact moment I hit temp for mash out. Out of curiosity I wonder what's considered the lowest effective mash out temperature

 

[RonnieBiggs]

Yeah I've started there by adjusting my mill gap a little larger, ill see how that goes.
I used to be a 3v guy myself but must say that an all in one system is not so much easier, a little more convenient for me though, definitely more compact and allows me to not take up the kitchen and stove are during the morning when I like to brew and the family likes to eat

Plus they don't see me running around with a spay bottle of Star San sprayin everything in sight like a lunatic lol

 

[doug293cz]

It does sound like cavitation I think?
Already opened the gap a bit and will see how that goes next time. Was coincidently weird that it happened almost the exact moment I hit temp for mash out. Out of curiosity I wonder what's considered the lowest effective mash out temperature

I believe that you can mash out at least as low as 167°F (75°C.) A related question is: do you really need a mash-out?

Brew on

 

[RonnieBiggs]

I believe that you can mash out at least as low as 167°F (75°C.) A related question is: do you really need a mash-out?

Brew on

Oohhh, we gonna need a separate thread lol

 

[RonnieBiggs]

Oohhh, we gonna need a separate thread lol

Habbits are the hardest thing to kick

 

[dmtaylor]

I believe that you can mash out at least as low as 167°F (75°C.) A related question is: do you really need a mash-out?

My 2 cents: As long as your crush is decent, and your mash pH in the acceptable range, and you plan to bring your collected wort to a boil immediately after the mash and not leave it sitting for many hours, then the mashout is probably an unnecessary extra step that can and should be eliminated.

 

[Pennine]

Are you pausing and stiring a couple times during the mash?

 

[Bassman2003]

The grain crush topic gets mixed up a lot between different systems people use. A good crush at a baseline needs to have all of the kernels opened up. Beyond that, you adjust your mill gap based upon lautering your most difficult brew. Meaning, tighten the gap until you have an issue then open it until the issue goes away.

There is no rule for the perfect crush. It is only about what you can get away with on your system. For my Foundry, I want to be able to lauter hefeweizen without needing to use rice hulls. So my system crush will be with a wider gap than someone who does not need to lauter wheat grists etc... And in general, I would say the AIO's do benefit from a wider mill gap than a narrow mill gap.

Also, a wider mill gap will make it easier to get clear mash wort. Some care about this, many don't. Bobby's recent test supported the idea that clear mash wort is a positive. So do not feel like one needs to go to flour because the BIAB folks are doing it!

Also, also, the mashout is more important for large breweries who put 2-4 entire mash lauters in a single boil kettle which results in the wort sitting for a long time as DM mentioned. That does not apply to us, but, the higher temperature does do a little bit more in mashing and b lowers the viscosity of the wort to aid in lautering. So I think a mashout is still worth doing.

 

[hungupdown]

The poorer the flow through the malt bed, the greater is the pump pressure needed to achieve flow, and so the greater the chance of cavitation.
I never ever, stir the malt bed, after it's rested and set.

I always get a very clear mash wort. Usually the bigger issue, is the trub after boiling.
I do a mashout, targetting 77°C for 10 min, but it usually only just gets there. But it means my 10min alpha amylase rest step, at 72°C, gets time to complete.
The mashout step, is meant to increase sparge flow rate.

 

[Cloud Surfer]

My malt loads in my 65L BrewZilla vary from 5kg to 8kg depending on the beer I’m making. I ended up developing a sliding scale for my mill gaps from 1.0mm to 1.2mm as the malt load increases. Now I get identical recirculation and lautering and sparging performance from batch to batch independent of how much malt I use.