Plz help w/ improving mash efficiency?

[Truman42]

I’m not sure if a slower motor speed alone will improve your efficiency any. I use a drill and crush fast especially crushing for a floating mash it fly’s through the mill.

A slower motor speed when going from drill 400 rpm to wiper motor 60 rpm didnt improve my efficiency it decreased it.

But it did stop my stuck mashes. The new motor which is around 150 rpm should give me a slightly better crush without having to change settings on my mill and hopefully give me better efficiency.
Of course I didnt add a new motor just to improve efficiency (Changing the gap could have done that) It just took to long to crush my grains with a motor going at 60 rpm with 8 kgs of grain.

Also I dont fly sparge I batch sparge and dont have any problems with channeling during the recirculation.

Motor speed does make a difference, I learnt that the hard way.

 

[S.E]

A slower motor speed when going from drill 400 rpm to wiper motor 60 rpm didnt improve my efficiency it decreased it.

But it did stop my stuck mashes. The new motor which is around 150 rpm should give me a slightly better crush without having to change settings on my mill and hopefully give me better efficiency.
Of course I didnt add a new motor just to improve efficiency (Changing the gap could have done that) It just took to long to crush my grains with a motor going at 60 rpm with 8 kgs of grain.

Also I dont fly sparge I batch sparge and dont have any problems with channeling during the recirculation.

Motor speed does make a difference, I learnt that the hard way.

Is it particularly difficult to open the gap[SIZE=11pt] a bit on your mill? [/SIZE]

Edit: Sorry forget that but In what way did motor speed make a difference?

 

[TimT]

I suspect heat loss from the esky may be your main problem too.

I just do my mash on a pot over the stove with a thermometer with a bit of a stir every now and then. Not sure if the stirring helps.... I had bad efficiency problems in the past, hardly ever getting to the predicted gravity. Now I simply mash twice and the second mash (in fresh water) seems every bit as effective as a sparge would be. (I suspect sparging was my main problem before; the second mash allows me to rinse out some of the remaining sugars from the first mash, and get some more enzymatic action - basically, what a sparge would do anyway.) It's not especially time-consuming. I let the first mash go for half an hour through to three quarters of an hour; same for the second mash. So yeah, you could try a second mash.

 

[Adr_0]

I suspect heat loss from the esky may be your main problem too.

Yeah, I think specifically air gaps.

Unless you're talking about Truman...

 

[Ducatiboy stu]

In what way couldn’t you get them to work for you, what problems did you experience? Do you mean they wouldn’t work at all or just bad efficiency or something?

Everything. Just could not get sucess. Its not to say there bad, it just didnt work for me. So I went false bottom.

 

[Ducatiboy stu]

How often do you get stuck sparges? It may be worth your while trying a courser crush if it’s happening a lot.

I prefer to crush as course as I can depending on the grain, if the grain kernels are pretty even in size I barely crack them at all. This results in a floating mash, when you mash in the hot liquor will make the grain expand and crack further. Air in the kernels help them float so most of the grain bed is floating above the manifold. On my system I get the best efficiency like this, my fly sparge is more efficient with less channeling.

If the kernels vary in size greatly I crush finer to crack the smaller ones though. Efficiency drops but not as much as leaving too many uncracked kernels.
.
Another advantage to the floating mash and course crush is you never get dough balls. Just tip the grain in and give it a very quick stir and put the lid on the mash tun ASAP. Actually its best to stir the mash as little as possible if you overdo it the grain bed will collapse and not float.

Once I got my crush sorted I got no stuck sparges. But after more than 200 mashes, you would hope so.

Stouts, due to the higher amounts of roasted grain can be a bit more tricky.

 

[JDW81]

As far as decoction mashing goes well that's very different because you are only handling a small portion of the mash at one time and you are using the grains when they have the most amount of sugars in them. The tannin trouble starts when you sparge with too higher temps and with a thin mash i.e if you sparge too long with the sparge water temps too high.

A decoction should be about 1/3 of the mash give or take, and it should be a very thick portion of it so you are actually boiling a lot of grain. Tannins aren't an issue if your pH is correct.

If you extract tannins at the end of a y sparge this has some to do with higher temps but more to do with rising pH as the run off gravity drops. Mash pH will rise as sparge run off gravity falls. If you control your pH then tannin extraction shouldn't be an issue.


JD

 

[Adr_0]

A decoction should be about 1/3 of the mash give or take, and it should be a very thick portion of it so you are actually boiling a lot of grain. Tannins aren't an issue if your pH is correct.

If you extract tannins at the end of a y sparge this has some to do with higher temps but more to do with rising pH as the run off gravity drops. Mash pH will rise as sparge run off gravity falls. If you control your pH then tannin extraction shouldn't be an issue.


JD

Without putting words in your mouth, if as a brewer you're likely to push pH up by doing a fairly drawn out/dilute fly sparge, it makes sense to make sure your mash starts at 5.2-5.3, rather than 5.5-5.7.

 

[Truman42]

Is it particularly difficult to open the gap[SIZE=11pt] a bit on your mill? [/SIZE]

Edit: Sorry forget that but In what way did motor speed make a difference?

The faster the motor the more it tends to rip apart the grain husks as they are pulled through the mill. So even with a gap of 1.2mm you can still rip your husks apart too much and have too much flour.
Like I said I didnt change motors just to change my grain crush, but getting the motor at a constant speed then working from there is the first step. My mill is a PITA to set the gap as its a cheapo and the adjustment knobs seem to have made grooves into the barrel. So even when I use a feeler gauge and set the gap to 1mm it tends to close up slightly as I tighten the adjustment lock nuts. I have to go 1.2mm to get it to close up to 1mm.

I think my other problem with a stuck mash was not having a ball valve on my MLT return. I now start off with the valve almost fully closed until I set the grain bed then open it up to 1/2 way and leave it like that for the entire mash schedule.

 

[Screwtop]

The faster the motor the more it tends to rip apart the grain husks as they are pulled through the mill. So even with a gap of 1.2mm you can still rip your husks apart too much and have too much flour.
Like I said I didnt change motors just to change my grain crush, but getting the motor at a constant speed then working from there is the first step. My mill is a PITA to set the gap as its a cheapo and the adjustment knobs seem to have made grooves into the barrel. So even when I use a feeler gauge and set the gap to 1mm it tends to close up slightly as I tighten the adjustment lock nuts. I have to go 1.2mm to get it to close up to 1mm.

I think my other problem with a stuck mash was not having a ball valve on my MLT return. I now start off with the valve almost fully closed until I set the grain bed then open it up to 1/2 way and leave it like that for the entire mash schedule.

As Truman says mill speed is also important. I use an adjustable 2 speed drill on the low speed setting with a low tech controller - a reusable zip tie around the handle and trigger to maintain around 250rpm

Screwy

 

[S.E]

As Truman says mill speed is also important. I use an adjustable 2 speed drill on the low speed setting with a low tech controller - a reusable zip tie around the handle and trigger to maintain around 250rpm

Screwy

I guess the maximum speed would depend on the mill you are using particularly the rollers. I I have a Mash Master now which is very well made and solid but I have noticed it doesn’t like to grip and pull the grain through particularly at higher speed compared to the barley crusher I used previously.

I use a drill by hand and just speed up slowly till it feels right, the barley crusher was always happier at higher speed the Mash Master tends to sand the husk down a little before pulling it through. Never had a problem with husks ripping apart with either mill though.

The fastest I’ve used was a commercial three phase with surprisingly short rollers, about 7cm long from memory, just cut the string on sack of grain tip it upside down on the hopper and it chew through it at warp speed.

 

[S.E]

Once I got my crush sorted I got no stuck sparges. But after more than 200 mashes, you would hope so.

Stouts, due to the higher amounts of roasted grain can be a bit more tricky.

I have never had a stuck sparge and make a lot of Irish stouts. I also vary my crush a fair bit. I made an Irish stout yesterday and closed the gap to the first mark on my MM mill (looks about 1.2mm-1.5mm I’m guessing) no stuck sparge but my efficiency dropped to 75%. Not blaming the crush entirely though I also stuffed up the sparge a bit and let the grain bed compact.

I believe false bottoms are more prone to stuck sparges than manifolds. I’m making myself a new MT with a false bottom so may start experiencing stuck sparges soon. I’m usually of the opinion if it’s not broken why fix it but want to try new brewing toys.

 

[Trevandjo]

I guess the maximum speed would depend on the mill you are using particularly the rollers. I I have a Mash Master now which is very well made and solid but I have noticed it doesn’t like to grip and pull the grain through particularly at higher speed compared to the barley crusher I used previously.

Slightly off topic. Why did you give up the Barley Crusher then? Reason being I'm trying to decide between the 2.

Trev

 

[S.E]

Slightly off topic. Why did you give up the Barley Crusher then? Reason being I'm trying to decide between the 2.

Trev

I didn’t give up on the barley crusher I think it gave up on us eventually. It belonged to another club member who semi donated it to the club after he turned pro and crushed all his grain at the brewery.

Anyone and everyone used it so it got very little rest and was quite worn last time I saw it. I bought myself the Mash Master, its well made and looks as though it will last forever but doesn’t crush as well or at least as fast as the barley crusher and other mills belonging to friends that I have used.

 

[Ducatiboy stu]

What size are the MM rollers diameter..?

 

[Ducatiboy stu]

I believe false bottoms are more prone to stuck sparges than manifolds. I’m making myself a new MT with a false bottom so may start experiencing stuck sparges soon. I’m usually of the opinion if it’s not broken why fix it but want to try new brewing toys.

The trick is getting the right size screen for your false bottom. If its to fine it will block up and if its to course the grain will fall thru. From memory I think the optimum hole size is 5/32" ( 3.9mm) with a ratio of about 50% opening. For a sloted FB the slot width is about 3/32 ( 2.3mm)..

Its not easy to track down the right perforated sheet so you may have to adjust your crush to suite whatever you can find.

This is why there are no real hard n fast rules as everyone has a different setup and its a matter of fiddling around to get things to work best.

 

[Ducatiboy stu]

Some interesting reading about lautering.

http://www.regional.org.au/au/abts/2001/w1/evans.htm

 

[Ducatiboy stu]

Some good reading in these articles

http://www.regional.org.au/au/abts/2001/w1/goldsmith.htm#TopOfPage

http://www.regional.org.au/au/abts/2001/w1/evans.htm

There are a number of good articles on that site that will help to improve your mashing and sparging/lautering.

 

[marksy]

How did the original poster go with all the responses?