Low Brewhouse Efficiency

[prongs_386]

Hi everyone,
I've just done my second all grain brew and I'm disappointed with the original gravity that I'm achieving.

I'm brewing 23 litre batches, the first time i only mashed 12 litres and sparged 18 litres and I ended up quite a bit short. So the second time I mashed 14.25 litres and sparged 24 litres and hit the 23 litre mark perfectly. I'm mashing at 75 originally which seemed to drop to 65...
The original gravity for both brews was 1.021 and my first brew had a final gravity of 1.06 giving me about 2.1% alcohol.. And the brewhouse efficiency was 33% for both brews.

I've heard that its normal for people to achieve up to 75% if they have a good system, and even poorer systems should still achieve 50-60%?

I have a Monster Mill and with the rollers as close as is allowed only about half of the grains seem to be split open.

My mash tun is a standard esky with stainless steel braid sitting along the bottom. I don't have a pump so I'm just batch sparging and my process is to drain off the wort and pour the first bit back onto the grains.. then i start pouring my sparge water over and draining constantly into the kettle. The sparge water seems to come out looking fairly colorless. I'm using a plastic container with holes drilled to allow the water to gently drop evenly onto the grain bed so its not being disturbed.


I was thinking for the next brew I might just use a higher mash volume and sparge less. Is someone able to explain what impact the mash vs sparge volumes has on the brew?

I'd really appreciate any tips on my process in general.

Thanks heaps.

 

[mxd]

A little more information will assist. (I would assume 5 kg grain ?)

but the gap on the mill should be around 1mm, you need to "crack" the grain slowly.

Try and order the grain cracked from (e.g G+G) and see if that assists, if it does then it may be your cracking, if not then sparging, temp, etc may need to be looked at. Also update your location, there may be someone close who you can watch do a brew.

good luck.

Matt

 

[bignath]

Someone with a lot more knowledge than me will most likely respond very shortly, but until then, i was wondering if your mash tun is operating properly? Is your sparge getting "stuck". obviously it would seem that 38+ litres of prepared water does seem way too much to only end up with 23 litres.

How dry is your grain bed at the end of your sparge process?

As i said, i am not as savvy with things like efficiency related questions like some of the more experienced brewers are, someone will chime in soon no doubt and be more helpful than me....

Hope you sort it out mate. The whole AG thing is well worth it when your system is working well.

Cheers,

bignath

 

[unrealeous]

I have a Monster Mill and with the rollers as close as is allowed only about half of the grains seem to be split open.

There's your problem. I don't have the same mill so can't assist in setting the gap - but 99% of the grains should be split.

Here's some photo's of what it should look like Linky

 

[manticle]

Hi everyone,
I've just done my second all grain brew and I'm disappointed with the original gravity that I'm achieving.

I'm brewing 23 litre batches, the first time i only mashed 12 litres and sparged 18 litres and I ended up quite a bit short. So the second time I mashed 14.25 litres and sparged 24 litres and hit the 23 litre mark perfectly. I'm mashing at 75 originally which seemed to drop to 65...
The original gravity for both brews was 1.021 and my first brew had a final gravity of 1.06 giving me about 2.1% alcohol.. And the brewhouse efficiency was 33% for both brews.

I've heard that its normal for people to achieve up to 75% if they have a good system, and even poorer systems should still achieve 50-60%?

I have a Monster Mill and with the rollers as close as is allowed only about half of the grains seem to be split open.

My mash tun is a standard esky with stainless steel braid sitting along the bottom. I don't have a pump so I'm just batch sparging and my process is to drain off the wort and pour the first bit back onto the grains.. then i start pouring my sparge water over and draining constantly into the kettle. The sparge water seems to come out looking fairly colorless. I'm using a plastic container with holes drilled to allow the water to gently drop evenly onto the grain bed so its not being disturbed.


I was thinking for the next brew I might just use a higher mash volume and sparge less. Is someone able to explain what impact the mash vs sparge volumes has on the brew?

I'd really appreciate any tips on my process in general.

Thanks heaps.

the first time i only mashed 12 litres and sparged 18 litres and I ended up quite a bit short. So the second time I mashed 14.25 litres and sparged 24 litres and hit the 23 litre mark perfectly. I'm mashing at 75 originally which seemed to drop to 65...


Not quite sure what this bit means. Can you explain more clearly?

I mash in with approx 2.5 L of water per kg of grain. General rule of thumb is 2.5 - 3 but I'm not sure why and BIABERs mash in with much more and still hit good efficiency levels. Another rule of thumb I don't know the reason for is to make your sparge at least half of your expected pre boil volume.

A few suggestions based on what you have written:

1. Sounds like you are fly sparging. I'd try batch sparging at least until you are familiar and comfortable with your processes. Read about batch sparging here: http://www.braukaiser.com/wiki/index.php/B..._Gyle_Simulator and here: http://www.grainandgrape.com.au/articles_o...ch_sparge01.htm . Fly sparging can give better efficiency but not if you do it wrong (I'm a batch sparger so I won't attempt to tell you how to do it right). What temp is your sparge water?

2. Getting water volumes spot on raher than approximate has helped my efficiency jump a bit. I've always been pretty consistently 70% but the things that have seemed to contribute to going up a few points are:

-accurate water measurements
-slightly finer grain crush
-calcium additions
-hotter sparge water
-protein rest and 2 step sacch rest

At this point I would just concentrate on getting the base process right before fiddling around with step mashing. if you can outline your process a bit more clearly it will help. Who crushes your grain?

What's your boil like - vigour, evaporation rate etc? Are you hitting final volume targets (or are you significantly under or over)? What are your expected efficiencies (what are you basing your recipe on)?

That's all the questions I can think of for the minute.

Just realised on re-reading that you crush your own grain but seem to be having trouble. Your grain needs to be cracked. Flour is not that great in general for tun mashers but neither is uncracked grain.

 

[MattC]

Are you using any brewing software??

Cheers

 

[raven19]

The sparge water seems to come out looking fairly colorless.

This sounds like possibly your temperatures are off, maybe not extracting anywhere near enough from the grains (i.e. colour and/or sugars). Can you check your mash temperature with another thermometer, etc?

I crush on the factory settings on my MM2, and get 70% efficiency.

 

[prongs_386]

Thanks for all the replies.

I am trying to batch sparge not fly sparge, my sparge water temperature is heated to 85 degrees and then i expect it to cool to at least 80 in the time it takes to get the sparging going.. So that's something I'm attempting to solve at the moment by buying a container to put my heated sparge water in so the kettle is free to drain the wort into.

I think when we crushed our grain originally we thought it was creating too much flour so we pulled it out a bit and then we ended up putting it all the way back in but its not crushing as fine anymore... I think I will have a play with this to try and get the gap closer.
Also after watching some more videos on the mash/sparge process I realised I wasnt stirring up the grain bed before letting the mash drain and then re stirring before letting the sparge water drain. I think that might help with getting more sugars from the sparge.

I think the problem is probably the grain crushing...


Also I think I lose about 0.5-1 litre in the bottom of my mash tun at the moment, the grain will absorb 5-10 litres I'm told and i will probably have 7ish litres of boil off.. I did originally use brewsmith to calculate my volumes however when we were so far off our mark i decided to just make them bigger for safety until I know my system better.

Also on my next brew I plan to accurately measure the water volumes at all stages so I know exactly where my water volume is ending up.


Thanks heaps for all the replies, I will re-post once I've been a bit more rigorous with my process and have tried cracking the grains more!

 

[raven19]

Let us know how the next brew goes. I hope you solve this dilemma!

 

[zebba]

when you say

I'm mashing at 75 originally which seemed to drop to 65...

do you mean that the water you are adding to the grain is @ 75 degrees to hit a mash temp of 65, or you are mashing @ 75 degrees (presumably adding water that is hotter again) and it drops to 65 over the duration of the mash?

also, re: the monster mill - how fast are you doing the crush? I found my mill had a pretty large gap between the rollers and the home-made base I made, so a fair bit of grain was getting thrown out of that gap and not going through the rollers. I just glued some scrap pieces of mdf I had leftover to close up that gap and the problem was solved.

 

[katzke]

Thanks for all the replies.

I am trying to batch sparge not fly sparge, my sparge water temperature is heated to 85 degrees and then i expect it to cool to at least 80 in the time it takes to get the sparging going.. So that's something I'm attempting to solve at the moment by buying a container to put my heated sparge water in so the kettle is free to drain the wort into.

(from original post) My mash tun is a standard esky with stainless steel braid sitting along the bottom. I don't have a pump so I'm just batch sparging and my process is to drain off the wort and pour the first bit back onto the grains.. then i start pouring my sparge water over and draining constantly into the kettle. The sparge water seems to come out looking fairly colorless. I'm using a plastic container with holes drilled to allow the water to gently drop evenly onto the grain bed so its not being disturbed.

The way I read it you are fly sparging, or possibly a combination of batch/fly.

But what do I know I BIAB.

 

[felten]

Beersmith says a strike temp of 75 with 12L of water and 5kg (that's only 2.4L/kg though) of grain should give you a 65 mash, if thats what you meant. (I'm still a little hazy on what you're doing)

If you are really seeing completely uncrushed grain, and not just whole husks with crushed endosperm inside, then its possible the grain may be leaking past your rollers somehow.

Your process in the OP for sparging sounds strange. Batch sparging is where you fully drain mash tun of the first runnings (with an inital vorlauf to get clear run off, which it sounds like you were doing) and then add your sparge water, stir it up, possibly wait a few minutes, and then repeat the vorlauf + draining.

Also the grain should only be absorbing somewhere around 1L per kg, so if you had 5kg of malt that would be 5L, not 5-10L

I'm probably repeating whats said above, and I'm only a lowly BIABer like katze so maybe I'm off on a few details, but your posts are just a little confusing to pinpoint a problem.

 

[tavas]

[/quote]
I think when we crushed our grain originally we thought it was creating too much flour so we pulled it out a bit and then we ended up putting it all the way back in but its not crushing as fine anymore... I think I will have a play with this to try and get the gap closer.
Also after watching some more videos on the mash/sparge process I realised I wasnt stirring up the grain bed before letting the mash drain and then re stirring before letting the sparge water drain. I think that might help with getting more sugars from the sparge.

I think the problem is probably the grain crushing...


[/quote]

I think from memory the MM2 comes with 0.040" gap setting (about 0.9 - 1 mm). You can check this with a set of feeler gauges from an auto parts store. Apparently Bunnings no longer sells them.
I left mine set at factory settongs and seems to crush well. I did notice on my last batch that it appears the grains aren't cracked, but after a quick run through with my hand, they broke up reasonably well.

 

[sipourit]

Grain crushing is really important in brewing.

@tavas
What machine do you use? Can I know it? That seems a nice crusher.

 

[tavas]

Grain crushing is really important in brewing.

@tavas
What machine do you use? Can I know it? That seems a nice crusher.

I use a Monster Mill MM-2. Its their base model 2 roller model. I specced it for stainless steel rollers and 1/2" drive to suit my drill, and also got the base and hopper. I can highly recommend the hopper, as I could never make something that good for $30 (others can, but not me. I'm a sheet metal tard). I bought mine direct from the states, paid about $250 all up delivered. Factory setting is about 0.9mm or 0.040", but you can adjust to suit. I haven't played with mine, as I'm trying to minimise all variables at this stage. But 0.9mm seems to work OK. I BIAB so I could go a little finer if needed, but at this stage I think there are other reasons why my beers suck, grind isn't one of them.

 

[amiddler]

Thanks for all the replies.

I am trying to batch sparge not fly sparge, my sparge water temperature is heated to 85 degrees and then i expect it to cool to at least 80 in the time it takes to get the sparging going.. So that's something I'm attempting to solve at the moment by buying a container to put my heated sparge water in so the kettle is free to drain the wort into.

I think when we crushed our grain originally we thought it was creating too much flour so we pulled it out a bit and then we ended up putting it all the way back in but its not crushing as fine anymore... I think I will have a play with this to try and get the gap closer.
Also after watching some more videos on the mash/sparge process I realised I wasnt stirring up the grain bed before letting the mash drain and then re stirring before letting the sparge water drain. I think that might help with getting more sugars from the sparge.

I think the problem is probably the grain crushing...


Also I think I lose about 0.5-1 litre in the bottom of my mash tun at the moment, the grain will absorb 5-10 litres I'm told and i will probably have 7ish litres of boil off.. I did originally use brewsmith to calculate my volumes however when we were so far off our mark i decided to just make them bigger for safety until I know my system better.

Also on my next brew I plan to accurately measure the water volumes at all stages so I know exactly where my water volume is ending up.


Thanks heaps for all the replies, I will re-post once I've been a bit more rigorous with my process and have tried cracking the grains more!

Brewmate is the software I used until I found my feet with Beersmith. Not as many tools to get lost in.
As said before messure your system (losses to mash tun/kettle and boil off) and use them in a calculator of some kind will help you hit your volumes. I have a 50L mash tun and kettle and have a 1 litre loss in both. I alow .9L per kilo of grain for absorbtion. My 45L boil I usually have 12% evaporation. Some ball park figures to get you going but you need to measure your own system.

Yes your biggest improvement will come from a much better grind. As said .9-1mm gap on your rolls and not alowing any grain to get past un-gruond.

Let us know how the next brew day goes. Chill, have another beer.

Drew

 

[prongs_386]

Hi everyone,

thanks for all the replies on this.
I did end up doing another brew about 2 weeks ago and had the same problem.

I adjusted the mill and made sure it was getting crushed properly for this latest one.

I think my mash temp might be off, I'm thinking of installing a mash master thermowell so I can monitor the temp for the entire mash.
The temp ended up being 65 rather than the 67 I was aiming for, but then at the end of the mash it had dropped to about 58.. even though my previous mashes hadn't dropped anywhere near that amount.


One of our problems is that I heat all my water in my 50l brew kettle because its the only thing I have that's large enough.. Then once the flame is out it takes us about 4-5 minutes to get the water into the mash tun and the lid shut after stirring etc... I'm also not sure how accurate my temp reading from the water in the pot is because my thermometer is fairly short so I have to take the reading from the top and I'm not sure what the average temperature is as opposed to the very top which I would assume is the hottest place apart from the very base with the flame on.


I also just have another query.. We got our first infection in our second AG brew. After our first brew the ash tun wasn't cleaned well enough and we had mold grow in there. Given that the wort gets boiled for an hour after going through the mashing process what is the chance that there is still some sort of infection hanging around?
Also how long does it take for bad smells/tastes to appear? When we bottled the beer it didn't smell or taste bad so I'm guessing its probably the bottles.

Thanks everyone for your help.

 

[manticle]

Stupid question maybe but you are adjusting for temp when you take your readings aren't you? (presuming you are using a hydrometer).

Would also be worth taking note of gravities at different points so you can see which bit of the process is off. Take SG of first runnings and total pre-boil runnings and see if you're hitting target.

 

[prongs_386]

Stupid question maybe but you are adjusting for temp when you take your readings aren't you? (presuming you are using a hydrometer).

Would also be worth taking note of gravities at different points so you can see which bit of the process is off. Take SG of first runnings and total pre-boil runnings and see if you're hitting target.

Hey, thanks for the reply..

I had previously looked into the difference by temperature and I thought that it wouldn't actually effect reading too much based on the change of density of water at different temperatures.. obviously I forgot to account for the change in density of the sugars at different temperatures, but I just used an online calculator that takes into account the temp and that showed the final alcohol to be over 6% given boiling temperature! We have been taking the reading after the boil.. I can't remember if we did it pre-chill or post-chill though.

We will make sure we measure the temp properly next time and take readings at different times.

Thanks heaps for your comment, hopefully our situation isn't as bad as we thought!

 

[prongs_386]

Stupid question maybe but you are adjusting for temp when you take your readings aren't you? (presuming you are using a hydrometer).

Would also be worth taking note of gravities at different points so you can see which bit of the process is off. Take SG of first runnings and total pre-boil runnings and see if you're hitting target.

Hey, thanks for the reply..

I had previously looked into the difference by temperature and I thought that it wouldn't actually effect reading too much based on the change of density of water at different temperatures.. obviously I forgot to account for the change in density of the sugars at different temperatures, but I just used an online calculator that takes into account the temp and that showed the final alcohol to be over 6% given boiling temperature! We have been taking the reading after the boil.. I can't remember if we did it pre-chill or post-chill though.

We will make sure we measure the temp properly next time and take readings at different times.

Thanks heaps for your comment, hopefully our situation isn't as bad as we thought!