Mashing Issues

[cdbrown]

After a year of brewing on the rig I'm now focused on improving my techniques to produce better and consistent beers, with consistency being an issue. And hopefully improve efficiency. The rig is a single tier 3v keg system with herms and 12" FB. I measured the millmaster gap at 1.42mm which is fairly wide considering most I've read have it around 1.1mm and some do two runs through the mill. It's connected to a 24vdc 250w bike motor which turns the mill at 160rpm so I'm not shredding the grain like I used to with a drill.

My main problem is the mash - compacting grain bed and stuck mashes. For all my brews the grain bed compacts down fairly quickly which then reduces the flow through the FB and also slows the temp rise within the MT. When I have left the mash for a while 15mins or so the bed get's really hard, just like trying to dig mud out of a hole - is this normal or would it suggest the bed is too compact?

This problem was even worse when I added a p-rest at 53C as the colder temps really make the bed hard as a rock. I'm starting to try and ignore the bed temp and just look at the HERMS pid despite how hard it is. The herms has no problems ramping temp easily 1c a minute if flow is unobstructed (freshly stirred mash), can be a few c a minute if the flow is reduced due to compact bed and slower flow. I've read plenty of posts that people only stir during mash in to get all grains sorted and remove doughballs, then leave it and maybe stir once again during mash out to help the temp increase.

I normally mash with 3L/kg but will increase this to 3.5L/kg for the brews which aren't too high gravity (got janets brown ale clone so will only be able to do 3L/kg). I want to include the p-rest to help with head retention and lacing in the glass. How long for the p-rest? Should it be dependent on the recirc rate through the herms? If the flow is 3L/min then after about 10mins there should be a full exchange through the herms? Most of the herms topics on this point to pumping as fast as possible so I have the valve fully open.

Ramp to sacc allowing 1c/min in the herms and ignore the temp lag of the mt? Have found that even though the herms may be at 66c the mt could be as low as 55 after the p-rest. Might take the full hour to bring the tun up to 66c. Will this affect the body? My previous brew took a long time for the MT to come up to sacc temp but herms was spot on - est FG was 1.011 but I ended up with 1.008. Leave it recirc for sacc for about 75min for coversion then ramp again at 1c/min up to mash out, hold for 10mins. Again ignore the MT gauge.

I batch sparge and have a feeling that draining the runnings to the keggle might be too fast. If I'm draining a double batch say 10kg grain, 35L water so theoretically get about 25L out after grain absorbtion - should I aim for 25mins to fully drain? Longer, shorter? At the moment I try to drain slowly but it still drains in about 10-15mins. I've read where people take 30mins+ to drain, then others that drain as fast as they can.

Planning on using rice hulls to open the bed a bit in future brews. Brewhouse efficiency fluctuates around 65-70%.

 

[peas_and_corn]

What sort of false bottom do you have?

 

[razz]

I have to disagree with you on pumping as fast as possible through the HERMS CD, I guess it's equipment dependant but that is asking for a stuck mash. My last few brews have had the first rest at 55 degrees and they have been fine, it won't be temperature that is causing problems. Start the recirc by just opening the ball valve until flow comes back to the MLT and then check the bed compaction every 5 minutes or so. If the flow is slow enough you shouldn't get compaction. I can't help on the batch sparge issue as I don't do it.

 

[Cortez The Killer]

A 2 step crush could help - with less husk shredding

Two equal drains of the mash tun will help with efficiency - it means your mash in ration is higher - but this could help with the compacting

Refer to this http://braukaiser.com/wiki/index.php/Batch_Sparging_Analysis and this http://braukaiser.com/wiki/index.php/Effec...nfusion_mashing

Mash tun drain time will not effect the efficiency with batch sparging - drain as fast as you can without compacting the bed

How are you returning the wort from the HERMS? Any issues with channelling?

Cheers

 

[cdbrown]

What sort of false bottom do you have?

12" s/s domed false bottom

I have to disagree with you on pumping as fast as possible through the HERMS CD, I guess it's equipment dependant but that is asking for a stuck mash. My last few brews have had the first rest at 55 degrees and they have been fine, it won't be temperature that is causing problems. Start the recirc by just opening the ball valve until flow comes back to the MLT and then check the bed compaction every 5 minutes or so. If the flow is slow enough you shouldn't get compaction. I can't help on the batch sparge issue as I don't do it.

Would I then have to increase the timing on this step for full recirculation? Asking this based on not hitting the target temp in the first place. I could choke the flow so it's just trickling through at maybe 1L/min or less but the tun would lag behind the herms alot. I guess I still can't understand that the brew will be ok if the herms is at 66c for the 60mins so that a small portion of liquid is at the right temp for a small period but 98% of the liquid and all the grains are well below that temp for that time, just doesn't make sense. Dropping the p-rest and making sure to hit the correct strike temp get's rid of this issue...

A 2 step crush could help - with less husk shredding
Two equal drains of the mash tun will help with efficiency - it means your mash in ration is higher - but this could help with the compacting
Mash tun drain time will not effect the efficiency with batch sparging - drain as fast as you can without compacting the bed
How are you returning the wort from the HERMS? Any issues with channelling?

Might try and go back to spraying warm water on the grains before milling and do a 2-pass mill.
What do you mean by two equal drains? The first runnings are generally a bigger volume than the 2nd runnings (batch sparge)
Herms is returned to the top of the mash and comes out a copper manifold I made - exits from 3 spots above the liquid level. I have no idea if there is channelling or not.

 

[kevin_smevin]

After a year of brewing on the rig I'm now focused on improving my techniques to produce better and consistent beers, with consistency being an issue. And hopefully improve efficiency. The rig is a single tier 3v keg system with herms and 12" FB. I measured the millmaster gap at 1.42mm which is fairly wide considering most I've read have it around 1.1mm and some do two runs through the mill. It's connected to a 24vdc 250w bike motor which turns the mill at 160rpm so I'm not shredding the grain like I used to with a drill.

My main problem is the mash - compacting grain bed and stuck mashes. For all my brews the grain bed compacts down fairly quickly which then reduces the flow through the FB and also slows the temp rise within the MT. When I have left the mash for a while 15mins or so the bed get's really hard, just like trying to dig mud out of a hole - is this normal or would it suggest the bed is too compact?

This problem was even worse when I added a p-rest at 53C as the colder temps really make the bed hard as a rock. I'm starting to try and ignore the bed temp and just look at the HERMS pid despite how hard it is. The herms has no problems ramping temp easily 1c a minute if flow is unobstructed (freshly stirred mash), can be a few c a minute if the flow is reduced due to compact bed and slower flow. I've read plenty of posts that people only stir during mash in to get all grains sorted and remove doughballs, then leave it and maybe stir once again during mash out to help the temp increase.

I normally mash with 3L/kg but will increase this to 3.5L/kg for the brews which aren't too high gravity (got janets brown ale clone so will only be able to do 3L/kg). I want to include the p-rest to help with head retention and lacing in the glass. How long for the p-rest? Should it be dependent on the recirc rate through the herms? If the flow is 3L/min then after about 10mins there should be a full exchange through the herms? Most of the herms topics on this point to pumping as fast as possible so I have the valve fully open.

Ramp to sacc allowing 1c/min in the herms and ignore the temp lag of the mt? Have found that even though the herms may be at 66c the mt could be as low as 55 after the p-rest. Might take the full hour to bring the tun up to 66c. Will this affect the body? My previous brew took a long time for the MT to come up to sacc temp but herms was spot on - est FG was 1.011 but I ended up with 1.008. Leave it recirc for sacc for about 75min for coversion then ramp again at 1c/min up to mash out, hold for 10mins. Again ignore the MT gauge.

I batch sparge and have a feeling that draining the runnings to the keggle might be too fast. If I'm draining a double batch say 10kg grain, 35L water so theoretically get about 25L out after grain absorbtion - should I aim for 25mins to fully drain? Longer, shorter? At the moment I try to drain slowly but it still drains in about 10-15mins. I've read where people take 30mins+ to drain, then others that drain as fast as they can.

Planning on using rice hulls to open the bed a bit in future brews. Brewhouse efficiency fluctuates around 65-70%.

I'd be draining alot slower then that. My fisrt brew with my new HERMS rig i ran off in about 10minutes and my efficiency was about 65%. When i slowed the run off down (it takes about 1hr to fill a 60L kettle while fly sparging) my efficiency jumped up to 85-90%.

I've only done about 6 brews with my HERMS but i haven't had a problem with a compacted mash bed. I dont run the pump at full speed. I would suggest that especially for the first 10 minutes or so of re-circ that you run your pump slowly to let the grain bed settle, you could probably then increase the speed a bit after that. I usually dont start the re-circ until the grain bed settles a bit anyway - about 5 minutes. I think it would be beneficial to let your malt properly hydrate before starting re-circ (as long as you mash in temp is spot on).

In terms of protein rest, i read in my Kunze brewing text (German fella who writes texts for commercial brewing) that the protease enzymes that positively influence head retention are most active I think at around 62 deg (it was definitely in the 60's). I know lots of people have reported good results doing p-rests in the 50's. I think Thirsty boy recommends 57 deg. I haven't compared the two mashing regimes so i couldn't tell you. If head retention is an issue for you it's probably way easier to just chuck some carapils/carafoam malt in.

Good luck with the trouble shooting

 

[Cortez The Killer]

Say for a 20L batch with 4kg of grain

Desired amount into kettle pre boil 26

So mash in with 4L+13L - that's a ratio of 4.25

This will yield 13L

Add another 13L to sparge and then drain 13L

So you have effectively performed 2 equal drains of the mash tun - giving you the best result per http://braukaiser.com/wiki/index.php/Batch_Sparging_Analysis

Thinner mashes do not cause issues in fermentability etc - and may help with the compacting

Cheers

 

[cdbrown]

I generally stick to double batches so the mash tun is nearly full with a 3.5L/kg ratio, plus I need to top up post boil with 10L to bring final volume up to 42L. Damn the 50L keggle. I could reduce the top up and increase the sparge volume and watch the boil like a hawk.

Will try the "no recirc" after doughing in and also the reduced rate.

 

[Wolfy]

Would I then have to increase the timing on this step for full recirculation? Asking this based on not hitting the target temp in the first place. I could choke the flow so it's just trickling through at maybe 1L/min or less but the tun would lag behind the herms alot. I guess I still can't understand that the brew will be ok if the herms is at 66c for the 60mins so that a small portion of liquid is at the right temp for a small period but 98% of the liquid and all the grains are well below that temp for that time, just doesn't make sense. Dropping the p-rest and making sure to hit the correct strike temp get's rid of this issue...

If you're having problems with grain bed compaction and stuck sparges, rather than pumping directly from the MT (which can cause suction and compaction of your grain bed) what about draining the MT via gravity into a separate vessel and then pumping from that back into the top of the MT?

 

[razz]

Would I then have to increase the timing on this step for full recirculation? Asking this based on not hitting the target temp in the first place. I could choke the flow so it's just trickling through at maybe 1L/min or less but the tun would lag behind the herms alot. I guess I still can't understand that the brew will be ok if the herms is at 66c for the 60mins so that a small portion of liquid is at the right temp for a small period but 98% of the liquid and all the grains are well below that temp for that time, just doesn't make sense. Dropping the p-rest and making sure to hit the correct strike temp get's rid of this issue...

I've never bothered to measure the return rate and hence the total time to recirc all the liquor CD. At a guess I return about 1-2 lts per minute. Yes, the mash does lag behind the temp at the HX but it's the temp of the liquor coming through the HX that you need to focus on. Eventually the tun catches up as more heat is applied through the HX generally by the 72 degrees rest or mash out, say 77 degrees.

 

[cdbrown]

I think I might go simple and drop the p-rest for a little while until i can get the single rest sorted.

For future brews - go for a thin mash, throw in some pre-washed/soaked rice hulls. Don't recirc for 5mins after dough in and then only do it slowly. Ignore the mash tun temp gauge. Drain to the keggle about the same rate as recirc to prevent the bed from compacting. I've never had a stuck sparge - perhaps that's due to channelling from the fast recirc and then fast drain?

Without actually stirring up the bed - is there a way to tell if the bed has compacted too much? Signs to look for?

 

[Thirsty Boy]

Rice hulls - absolutely, they help significantly. I use lots of them.

Higher L:G ratio, yes, helps too - I'm running my RIMS between 3.5 and 4-1 L:kg

Flow rates - As high as you can go... without getting compacted mash issues. The higher the flow rate, the smaller the time difference between your heat-ex temp and the mash tun catching up, and IMO the more consistent your brews and the tighter your temp control.

Getting that flow rate - can really be a matter of technique on starting your pump up. Always start with a really low flow rate, just barely trickling through... then over 5mins or more, tweak the valve open till you are getting a good flow rate, keep an eye on the mash and make sure it doesn't suck down onto the plates too hard.

I always mash in at a high (55-56) P rest - one of the reasons is that it gives me a chance to get the flow rates all set. So, I calculate the dough in temps like a single infusion brewer would, get the grains into the water, stirred in and settled. Then start the recirc nice and gentle. By the time I have the recirc all sorted, 5 or so minutes of mash time have passed and I'm set to start ramping to my first conversion rest.

Goo on top of the mash - depending on a couple of things, you can get a bit of a layer of fine "mud" build up on top of the grain bed. This kind of seals the top of the bed and can make the whole kit and kaboodle suck down onto the plates. One of the reasons why commercial lauter tuns have rakes. You can do much the same as rakes by poking holes in the top of the mash or cutting it with a spatula/knife in a diamond pattern with 1-2cm gaps. just go an inch or two into the grain bed so you dont mess up your wort clarity. Cutting deeper into your grain bed (but still stopping short of hitting the bottom) is another way to get better flow rates and not compacting your bed.

Draining your tun - if you are batch sparging, and I assume stirring your mash when you add your sparge water, then the rate at which you drain the tun should make absolutely no difference whatsoever to your efficiency, thats not how batch sparging works. If you aren't stirring the mash when you add the sparge water, just putting it on top, you're sort of flood sparging rather than batch sparging as its normally understood, and you will need to drain closer to the rates a continuous sparger would, this might also be contributing to your hard grain bed post sparge, the high differential pressure accross the grain bed from putting all the water on top can make it compact and stick.

Low hanging fruit is in my opinion - lots of rice hulls, higher L:G and most importantly, care in setting up your flow rates at the beginning of your mash.

Good luck

TB

 

[cdbrown]

Goo on top of the mash - depending on a couple of things, you can get a bit of a layer of fine "mud" build up on top of the grain bed. This kind of seals the top of the bed and can make the whole kit and kaboodle suck down onto the plates. One of the reasons why commercial lauter tuns have rakes. You can do much the same as rakes by poking holes in the top of the mash or cutting it with a spatula/knife in a diamond pattern with 1-2cm gaps. just go an inch or two into the grain bed so you dont mess up your wort clarity. Cutting deeper into your grain bed (but still stopping short of hitting the bottom) is another way to get better flow rates and not compacting your bed.

Draining your tun - if you are batch sparging, and I assume stirring your mash when you add your sparge water, then the rate at which you drain the tun should make absolutely no difference whatsoever to your efficiency, thats not how batch sparging works. If you aren't stirring the mash when you add the sparge water, just putting it on top, you're sort of flood sparging rather than batch sparging as its normally understood, and you will need to drain closer to the rates a continuous sparger would, this might also be contributing to your hard grain bed post sparge, the high differential pressure accross the grain bed from putting all the water on top can make it compact and stick.

Cheers.

There's always a layer of "mud" or grain powder over the grain after draining. One thing I remember from the last brew is that as the pump basically sucked down the grains there was about 10cm of liquid sitting above it. If I just let the bed settle nicely and not compact through a slower recirc rate, should the grain level look higher. I see pics on the web with the grain level being pretty much at the top of liquid level - is this what I am looking for? Is the large difference in grain level to liquid level a good indication of too much compaction?

I always stir after adding the sparge water, then recirc for 10mins before draining.

 

[Thirsty Boy]

Cheers.

There's always a layer of "mud" or grain powder over the grain after draining. One thing I remember from the last brew is that as the pump basically sucked down the grains there was about 10cm of liquid sitting above it. If I just let the bed settle nicely and not compact through a slower recirc rate, should the grain level look higher. I see pics on the web with the grain level being pretty much at the top of liquid level - is this what I am looking for? Is the large difference in grain level to liquid level a good indication of too much compaction?

I always stir after adding the sparge water, then recirc for 10mins before draining.

in the "perfect" scenario, your grain bed would be predominantly floating and the grains would only just be under teh liquid level. I've managed that a few times, but not usually. how far under the liquid level will depend on your l:G and the shape of your tun. Mines lower and flatter than a keg and I probably have about 5cm or so?? about?

poke holes in that mud!

dont be frightened to stir up your mash either - if you think things are getting stuck, cut the re-circ and have a feel around in there with your mash paddle to see if its loose and fluffy or too solid - if its too solid, stir it up and have another crack. no rules to say you cant.

 

[yandy5000]

Don't get too caught up in the details, it's more like cooking than it is hardcore science. I found a large fine mesh grain bag solved all my problems and malts are so good now sparging could just mean extra time and trouble. That's just my opinion though, go nuts!

best regards,
Yandy

 

[DWC]

Don't get too caught up in the details, it's more like cooking than it is hardcore science. I found a large fine mesh grain bag solved all my problems and malts are so good now sparging could just mean extra time and trouble. That's just my opinion though, go nuts!

best regards,
Yandy

Doesn't matter how good modern grains are.
Sparging rinses leftover sugars out of mashed
grains.

Dave

 

[dr K]

FWIW
Since moving to a HERMS system I have found that I have a better result at 2.8:1 L:G than my trad 2.2:1, no doubt I would be fine at 3+:1.
TB nails it with the floating mash, this really is ideal, a very coarse crack helps achieve a good float (not certain about efficiency, I do not aim to for high efficiency, grain is cheap, I stop sparging relatively high, say 1018ish.)
To achieve a fast ramp at a high flow rate you have to have a lot of wort in the herms heater. I for example have 5meters of 12mm copper coil running through a 10 litre urn, I use a march pump knock off that probably runs at a maximum rate of 15 litres per minute, which means, at that rate my wort has about 2 seconds of contact with the HERMS water, even if the HERMS urn is boiling my wort is not going to heat up, in fact it will probably cool. If I had 100 meters of coil I would have some 11 litres of wort in the coil with an heat exchange time of about 45seconds and a dry bed !
I run a very gentle HERMS for about 60 minutes , with the temp robe at the wort return point, the flow is directed tangentially to the side of the round SS tun with full false bottom. I turn off the pump, let the bed relax for 15 minutes then slowly sparge.
Works for me

K

 

[Thirsty Boy]

Interesting about letting the bed relax Dr K - is it something you've tried both ways and noticed a difference?

I'm pumping from MT to kettle and only pause long enough between ending my mashout (constant re-circ during whole mash) to swap the hoses from re-circ to sparge configuration. When i have things cherry ripe and the bed is in really good shape, if not actually floating - during that pause sometimes a grain bed thats been pulled down onto the plates a little, will re-float. I guess it makes sense that without the constant downwards force of the pumping, the boyancy of the grain bed, floating or on the bottom, would tend to expand it a little, and that'd let the sparge penetrate better.

I might give that 15min pause a run next brew. Thanks for the tip.

 

[MHB]

Braumeisters have a programmed in pause in the pumping at regular intervals during the mash cycle, very much for the reasons Dr K and TB are talking about. You can sometimes see a noticeable change in the flow rate before and after the pump pause.
My system before the Braumeister was a pump recirculated system but with a heated jacketed tun so in effect very similar to a herms/Braumeister approach I found that cracking quite coarse was best (around 1.5 mm), a very gentle crush that made very little flour kept the bed highly permeable and didnt reduce efficiency too much.
You have to wonder if mashing in at Protein degrading temperatures is going to help with the Mud there is a very good possibility that a lot of the mud is condensed protein (basically early break material) mixed in with fines. A 50oC ish rest could be fluidising a lot of this material.
Oh and lots of Calcium in your water (75-100 ppm), seams to make for a much more fluid bed. I have taken to adding a touch of Zinc and a teaspoon of Yeast Nutrient (not DAP the other one) to the mash, it contains a bunch of trace elements that act as Enzyme Cofactors just doing this has picked up 3-4% in overall Brewhouse Yield
As with most things brewing there wont in all likelihood be a single answer, but a combination of factors that will help to dramatically improve your system.
Have fun working out what works best for you; every system is unique and will represent an individual set of conditions to work at is best.
MHB

 

[Bribie G]

Slightly :icon_offtopic: MHB your inboxes have been full, so I'll ask you on the forum - re calcium lactate, have you guys been doing any more experiments with it? I'd be interested in trying some to boost mash calcium levels. I've found out that they use it widely in food processing -e.g. calcium boosted orange juice - and it's basically tasteless.
Interested in a calcium boost without changing the chloride / sulphate ratio in the mash.