Help! Low efficiency, grain crush??

[Nelson81]

Hi folks,

I have just finished my second all grain brew on a 30L Klarstein Mundschenk (Hopcat/Ace/Brewdevil etc)....I purchased all ingredients from the Malt Mill, enough for 2 x Kolsch style brews...my basic recipe and method as follows:

Default
72% efficiency
Batch Volume: 23 L
Boil Time: 60 min
Mash Water: 18.5 L
Sparge Water: 14.3 L
Total Water: 32.8 L
Boil Volume: 28 L
Pre-Boil Gravity: 1.044
Vitals
Original Gravity: 1.050
Final Gravity: 1.009
IBU (Tinseth): 22
Color: 7.1 EBC
Mash
Temperature — 65 °C — 60 min
Malts (5 kg)
4.5 kg (90%) — BestMalz Pilsen Malt — Grain — 3.5 EBC
500 g (10%) — BestMalz Vienna — Grain — 9 EBC
Hops (78 g)
50 g (19 IBU) — Saaz (Whole) 3.62% — Boil — 60 min
28 g (3 IBU) — Hallertauer Hersbrucker (Whole) 2.9% — Boil — 10 min
Yeast
1 pkg — Fermentis K-97 SafAle German Ale

Now on my first attempt, everything was followed down to a tea - my hours of relentless research and homework seemed to pay off - every step went as planned - I checked my OG after chilling wort to pitching temps and it was 1.042, estimated 62% brewhouse efficiency?

Attempt two, exacting the same recipe and set-up, this time I adjusted the flow rate of the pump during the mash (was rising and going through the central overflow pipe quickly during attempt 1), I also made a point of giving the gist a good stir 20mins into the mash.......again I took a reading post chill, 1.042, identical!

Could anyone possible pick any holes in the method/recipe? My only thought is that the grain looked very lightly crushed, should I have selected the fine crush option on the Malt miller website as opposed to the standard crush?

Any help would be most appreciated! Thanks, Neil.

 

[Slid]

I've only recently started crushing my grains myself and an early attempt got me 61% BH efficiency due to a crush that was not fine enough - too big a gap between rollers.
So, I would say that it is potentially a contributing factor.
Also, if you got the same outcome twice and have done other recipes on the same equipment at > 70%, the crush looks like the culprit!

Only thing I can think of to do now would be to add DME to compensate. 500g should get you pretty close to target.

 

[Nelson81]

I've only recently started crushing my grains myself and an early attempt got me 61% BH efficiency due to a crush that was not fine enough - too big a gap between rollers.
So, I would say that it is potentially a contributing factor.
Also, if you got the same outcome twice and have done other recipes on the same equipment at > 70%, the crush looks like the culprit!

Only thing I can think of to do now would be to add DME to compensate. 500g should get you pretty close to target.

Many thanks for the reply! I'm guessing it would be too late to add DME now? Batch one is 5 days into fermentation, and the other is one day in.....These are the first two all-grain brews I have done, I have ingredients enroute for an oatmeal stout, have chosen the finely crushed option so we shall soon see!

 

[Slid]

Many thanks for the reply! I'm guessing it would be too late to add DME now? Batch one is 5 days into fermentation, and the other is one day in.....These are the first two all-grain brews I have done, I have ingredients enroute for an oatmeal stout, have chosen the finely crushed option so we shall soon see!

I would leave #1 alone now, but 500g just sprinkled into #2 might be a better bet. The DME is not going to still be floating on the top in 12 days time!

 

[Rodcx500z]

The good thing is you have beer, 1042 og if you get it down to 1009fg you will have a beer of 4.33 abv so all is not lost, looking at the water you have 28L pre boil wort and 23L to fv, I have a klarstein fullhorn biab system and only get 3.5L per hour boil off you have 5 which would account for the low og

 

[The Baron]

Hi I would think that the fine crush is usually for BIAB brewing and it may cause a stuck mash in your system but only guessing as my supplier does a standard crush which suits my system (the same as yours) most of the time. If you find that you do get the level rising during re-circing and it goes down the centre overflow pipe even after stirring the mash I would just persevere with it (will not be the best brew day). If after all that your efficiency is still similar to the last 2 brews then it is not the crush you would think but having said that it is not flowing through the grain so you really need the water/wort to flow through the grain bed.
If by any chance the EFF is better and it should be with a finer crush and you are happy with it but are getting a stuck sparge you can try and combat this with using rice or oat husks in the grainbill this will create more space between the grains for water to flow.
If you EFF is still the same it could just be not the best batch of grain you have got which can happen. I generally get 70% minimum and sometimes higher but I also find that lager malts do sometimes give a slightly lower EFF but only slightly also it may take you a while to perfect the best way for you to use your system for a better EFF and tweaking things over time may get you there.
I did not really do much that I noticed or could put my finger on but I obviously improved my technique over a few brews to get to a nice reliable EFF of 70% plus which is what I set in my recipe builder as standard
Apart from that it has got to be the either the crush, sparging method may be worth looking at or a bad/low EFF grain. Let us know what your stout does as that will be using Pale malt as a base I would think and don't forget the overflow pipe is what it is named for and your water/wort should not be running down this as it is meant to go through the grain again this would give a poor EFF as it is not rinsing through the grain bed

 

[Nelson81]

Hi I would think that the fine crush is usually for BIAB brewing and it may cause a stuck mash in your system but only guessing as my supplier does a standard crush which suits my system (the same as yours) most of the time. If you find that you do get the level rsing during re-circing and it goes down the centre overflow pipe even after stirring the mash I would just persevere with it (will not be the best brew day). If after all that your efficiency is still similar to the last 2 brews then it is not the crush. If by any chance the EFF is better and it should be with a finer crush and you are happy with it but are getting a stuck sparge you can try and combat this with using rice or oat husks in the grainbill this will create more spce between the grains for water to flow.
If you EFF is still the same it could just be not the best batch of grain you have got which can happen. I generally get 70% minimum and sometimes higher but I also find that lager malts do sometimes give a slightly lower EFF but only slightly also it may take you a while to perfect the best way for you to use for better EFF and tweaking things over time may get you there.
I did not really do much that I noticed or could put my finger on but I obviously improved my technique over a few brews to get to a nice reliable EFF of 70% plus which is what I set in my recipe builder as standard
Apart from that it has got to be the crush, sparging method may be worth looking at or a bad/low EFF grain. Let us know what your stout does as that will be using Pale malt as a base I would think and don't forget the overflow pipe is what it is named for and your water/wort should not be running down this as it is meant to go through the grain again this would give a poor EFF as it is not rinsing through the grain bed

Thanks for this! During the second batch, I partially closed the tap on the re-circulation pump to maintain a steady level, as I was convinced this was the cause for the low SG.......

Sparge water was at approx. 76 degrees both times, gently poured over the perforated top grain plate.....

This is the grain bill for the next brew (fine crush specified), fingers crossed!....

4.8 kg (72.3%) — BestMalz Pale Ale — Grain — 6 EBC
700 g (10.5%) — Harraway's Rolled Oats — Grain — 2 EBC
500 g (7.5%) — Crisp Chocolate — Grain — 950 EBC
500 g (7.5%) — Crisp Crystal Extra Dark — Grain — 340 EBC
140 g (2.1%) — BestMalz Roasted Barley — Grain — 1300 EBC

 

[cushyno]

Recently I purchased a "Corona" style grain mill off eBay, cheap as chips. I took the plunge into milling to see if I could improve the consistency of efficiency. With grain from some suppliers a have achieved 70%+ and from others I'm down at 63% and it even varies per bag of crushed grain from the same supplier at times.

The batch before I purchased the mill had achieved something like 63% efficiency when expecting 67%, so gravity was out and I had to add DME to the boil as Slid suggests.

First batch with grain that I had milled was at about 74% BH Eff. That's with the same process and same grain batch, but with the pre-crushed grain passed through my own mill at a finer crush.

Second batch with home-crushed grain got 73% BH Eff. So I'm starting to see the consistency I wanted straight away.

 

[The Baron]

Did you say you had the re-circ pump tap fully open if so that is why you got the water/wort rising as you will need to throttle it back to get a happy medium of re-circ to grainflow.The amount you throttle back will be determined by the grainbill size and the actual grains/adjuncts such as Rye malt will cause a stickier mash as will rolled oats so this is where you really start to learn how to build a recipe to suit your system. I use 200 to 300g of rolled oats in nearly every brew to help with body/mouthfeel and bear in mind you have 700g in the stout recipe so be prepared to throttle it back a bit more than normal as they go sticky when wet just like porridge for a want of words but a higher amount of rolled oats is what is required in a stout to give that nice thick smooth mouthfeel so do not be alarmed but you now know what to watch for.
Good luck and keep us informed as the more info you post the more chance somebody can throw a solution your way

 

[The Baron]

Recently I purchased a "Corona" style grain mill off eBay, cheap as chips. I took the plunge into milling to see if I could improve the consistency of efficiency. With grain from some suppliers a have achieved 70%+ and from others I'm down at 63% and it even varies per bag of crushed grain from the same supplier at times.

The batch before I purchased the mill had achieved something like 63% efficiency when expecting 67%, so gravity was out and I had to add DME to the boil as Slid suggests.

First batch with grain that I had milled was at about 74% BH Eff. That's with the same process and same grain batch, but with the pre-crushed grain passed through my own mill at a finer crush.

Second batch with home-crushed grain got 73% BH Eff. So I'm starting to see the consistency I wanted straight away.

What Cushyno says is correct you can get inconsistencies in grain crush even from the same supplier, I have only had this once from my supplier and I have had loads of sacks from them so I just put that down to experience so finding a supplier that suits you is best and stick with them unless you want to go down the crush your own in which case you will get the best crush to suit you.
I personally do not have the time or inclination to crush my own but some swear by it, its your choice
Ps I tend to get 74/75% most of the time but set my recipe builder to 70% that way I can either have a slightly higher ABV or can back liquor to get to my original OG, it just gives me that bit of allowance to play with once I have finished the boil

 

[Rodcx500z]

Agree with all above, but I would still check the boil off rate, just fill your kettle and boil it on the setting you use when brewing, measure 25L water boil for 1 hour and measure whats left

 

[Rodcx500z]

Also have you accounted for dead space it all adds up

 

[The Baron]

I think the boil offrate is ok Rod as I pointed him in the right direction regards profile for his machine as it is the same as mine and the figures he has at the top of the post are bang on so I think we can dismiss that one but good ask

 

[The Baron]

One question that has just sprung to mind with what Rod has said is am I right in saying they were kits from MM and where they 23lrs grainbill kits or where they for 20/19Ltr brews? if the latter that is where the dilution of the OG may have happened

 

[Nelson81]

Also have you accounted for dead space it all adds up

Thanks for the suggestions! I used the parameters from brewfather, they seem to be correct for my equipment going by other posts I have seen.....regarding the boil off, I know its not an ideal method of checking, but I made it 5L by the etchings inside the machine?

 

[Nelson81]

One question that has just sprung to mind with what Rod has said is am I right in saying they were kits from MM and where they 23lrs grainbill kits or where they for 20/19Ltr brews? if the latter that is where the dilution of the OG may have happened

I created the recipe first in Brewfather for a 23L batch, then just ordered double the qty required online from Malt Miller for the two brews....

 

[Rodcx500z]

The only reason I mentioned boil off I had this problem when I first got my kettle, just had a look on malt miller they are for 23L I would start simple and weigh the water on bathroom scales 1 kilo = 1 litre and go from there

 

[The Baron]

did you get 23ltr to the Fv then and how much trub/waste was in the Klarstein?

 

[Nelson81]

did you get 23ltr to the Fv then and how much trub/waste was in the Klarstein?

Just shy of 23L (22.8ish?)......Not much waste at all in the kettle, used muslin bags for the hops - so filled the FV using the re-circulation pump....both batches were identical regarding FV volume...

 

[The Baron]

Looks like you have got things spot on there thats what I would get with probably at max a litre of trub/waste at the most. Lets see what happens with the next brew but having time to think it may be that some of re-circ was bypassing the grainbill and not rinsing all the sugars out, maybe the grain was too coarsley crushed as well,we will see.
By the way how many options does MM give for crushing?