All Grain Efficiency Very Low - What am I doing wrong

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NzBrewerMatt

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Hi all

Hoping you can help.
I'm currently brewing on a three-tier system consisting of 3 56L stainless steel kettles.

Unfortunately, I'm getting a really bad efficiency. Yesterday I did a brew and it came out at about 58% efficiency.

I did a SMaSH recipe which is below;

Batch Size: 23L
Strike Water: 17.5L
Sparge Water: 18.5L

6.5kg Golden Promise Malt
30g Mosaic @ 60mins
40g Mosaic @ 15mins
1g Kopperflock @ 15mins
40g Mosaic @ 0mins

1x US-05 yeast.

I did the following steps;

1. Heated 17.5L of strike water to 74 degrees.
2. Mashed in at 68 degrees
3. Let the mash sit for 60 mins. Did not stir it during this time.
4. Recirculate using a pump. Valve was open fully. Recirculated into the top of the mash tun into a strainer with holes in the bottom of it. Recirculated for 15mins
5. Drained all of the wort in the mash tun to the boil kettle.
6. Added about 18.5L of sparge water and stirred this through the grains. (Batch Sparge)
7. Let the sparge water sit in the mash tun for about 30 mins.
8. Recirculated the sparge water using the same process as listed in step 4. Recirculated for 15 mins.
9. Drained the sparge water into the boil kettle.
10. Boiled the wort and added hops.
11. Using an immersion chiller, cooled down to 20c.Took about 45mins.
12. Took OG which came in at 1.052 where I was aiming for about 1.058 - 1.060. (Beersmith had been advising I should be around this OG).

This brew day came in at about 58% which is seriously low. Is there anything from the above that I'm not doing right or should look to change?

I've read in some places that having the values open completely allowing the wort to come out quite quickly during the 15min recirculation can hurt efficiency? I've also heard that stirring during the mash can help increase efficiency.

My water profile is below:
Calcium: 7.7
Magnesium: 1.6
Sodium: 8.7
Chloride: 13.08
Sulfate: 7.97
Alkalinity: 18

I've never really paid much attention to the pH but have seen this could also cause some issues.
Hoping this is enough information for you guys.
 

Liam_snorkel

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what volume of wort did you end up with in the kettle?
It's just as likely to do with managing your losses (mash tun dead space, kettle trub) rather than mash conversion.
Get in the habit of measuring your kettle volume and specific gravity pre-boil as well, this will help you pinpoint what's going on.
 

malt junkie

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Ph and salts can knock your efficiency, but at most 5-10 points. The most likely cause is your crush, if you mill yourself mill a couple hand fulls and take a pic for us. If your grain is milled by your LHBS try a different supplier, I'd recommend any of our site sponsors. You haven't given us too much idea on your mash tun setup F/B? manifold? Linear flow through the bed can also cause efficiency issues. And as above check your loses volumes across your system.

When recirculating any mash:
  1. mash in allow the mash to rest 5-10 min (this allows the grain time to absorb the water)
  2. when first starting the pump, close the outlet to max 1/3 open
  3. SLOWLY over 10-15 minutes open the valve to desired flow (i'm yet to see any reason to be going flat out unless your using rims or herms and trying to step temps).
 

NzBrewerMatt

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what volume of wort did you end up with in the kettle?
It's just as likely to do with managing your losses (mash tun dead space, kettle trub) rather than mash conversion.
Get in the habit of measuring your kettle volume and specific gravity pre-boil as well, this will help you pinpoint what's going on.

Ended up with about 27 or so litres in the kettle. About 22 litres made it into the fermenter.

Yeah I did suspect that about the mash tun dead space. My mash tun does have a dome style of false bottom that only covers up about 2/3 of the mash tun bottom.

I also suspect some of the values I might have set in BeerSmith to be wrong. (E.G Trub loss)
 

NzBrewerMatt

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Ph and salts can knock your efficiency, but at most 5-10 points. The most likely cause is your crush, if you mill yourself mill a couple hand fulls and take a pic for us. If your grain is milled by your LHBS try a different supplier, I'd recommend any of our site sponsors. You haven't given us too much idea on your mash tun setup F/B? manifold? Linear flow through the bed can also cause efficiency issues. And as above check your loses volumes across your system.

When recirculating any mash:
  1. mash in allow the mash to rest 5-10 min (this allows the grain time to absorb the water)
  2. when first starting the pump, close the outlet to max 1/3 open
  3. SLOWLY over 10-15 minutes open the valve to desired flow (i'm yet to see any reason to be going flat out unless your using rims or herms and trying to step temps).
The grain crush happens at my LHBS. I inspected the grains and they looked to be crushed well.

My mash tun is 56L and has a domed false bottom as pictured below. When I recirculate, I'm recirculating into a strainer pot sort of thing that disperses the wort. Not sure how effective this is, however.
 

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Liam_snorkel

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Ended up with about 27 or so litres in the kettle. About 22 litres made it into the fermenter.
27L post-boil? You're leaving a lot of wort behind if only 22 makes it into the fermenter. I generally try to only leave 2-3L behind, max.
All else being equal, if you sparged with 3L less, your OG would have been around 1.058
 

NzBrewerMatt

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27L post-boil? You're leaving a lot of wort behind if only 22 makes it into the fermenter. I generally try to only leave 2-3L behind, max.
All else being equal, if you sparged with 3L less, your OG would have been around 1.058
Yeah, I think it was about 26-27 litres post boil. Unfortunately, i don't have a site glass on the kettle so I can't exactly tell.Also, I think I'm losing about 3-5 litres during the boil.
 

Liam_snorkel

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You may also just be overfilling the kettle, remembering that the sparge runoff is going to be much lower gravity.
Maybe try marking the inside of the kettle with your target pre-boil volume and stop the runoff when it is reached, and go from there.

you can use a steel ruler to measure kettle volume.
V = pi/4 (D)^2 x d
where D is diameter of kettle, and d is the liquid depth. You only need to do this calculation once to get a conversion factor for depth to volume (and vice versa).
 

NzBrewerMatt

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Yeah, I'm going to stop by a place today to see if I can get some stainless steel bars that I can use to make a measuring stick with. I'll test with properly marked water and will make the spots on the bar.
 
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Just get a 600mm long stainless steel ruler and add water to your kettle with a large metric jug, which you are certain is accurate.
Make a note of the volumes which you can then mark on your ruler with a permanent marker.
If you make a note of every 10 litres, you can work the rest out afterwards.

23738002_1591550400903054_2998763655456958679_o.jpg
 

TheWiggman

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Your brewhouse efficiency depends on the 2 things - the original gravity and volume. If you do in fact have 27 litres in the kettle then your mash efficiency isn't probably all that bad. If you were able to get every last drop in the fermenter this would correspond to 70% efficiency. Looking at your process it looks like you're doing everything right in your process and you probably should be hitting around 75-80%.

First things first, double check all your measurements and ensure the measuring devices are calibrated correctly. Are you using a hydrometer or refractometer? Have you checked them against another device or calibrated them? Are your water measurements accurate? If one or more things are out correct them and try again.

Once that's been ruled out, make sure the crush is good. A poor crush will have a significant impact on efficiency. I won't explain it, there's plenty of info out there on what to look at for a good crush (like this page). An experienced AG brewer can provide good input.

Lastly, check the gravity at a few steps of the process so you can target where you might be going wrong -
  • First runnings after the mash cycle
  • Gravity and volume before the boil
  • Gravity and volume after the boil (in the kettle)
  • Volume into the fermenter (which is what's used to determine brewhouse efficiency)
Once you have all the above come back to us and I'm sure you'll get a straight answer.
 

timmi9191

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My suggestions fwiw.
1. Measure mash ph
2. Double batch sparge
3. Check grain bed for channel ing as that false bottom may be concentrating the draw.
4. Slowly ramp up the recirc rate so grain bed can settle without channelling
5. Extend the pick up under the falsey to minimise dead space
6. Mash with pants off
 

2cranky

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You can measure all your losses and adjust your brew rig profile in BeerSmith. If you haven’t already done so you need to do this. I just used a galvanised bar from Bunnings as my measuring stick (I’ve seen other guys just mark their mash paddle). I have the mash tun marked on one side and the kettle marked on the other. I used a 5l jug to measure in 5l increments. I then filled 1l in between.
Once I had my mash filled with the marks on my stick I emptied 5l at a time into the kettle. I marked the other side of my stick at each 5l and at the end I recorded the loss. This is what’s left in the mash tun. I then measured it out of the kettle and took note of my kettle loss.
But I always adjust my sparge volume depending what volume I get from my first runnings. I think a sight glass on my HLT would help here.
I don’t recirculate but I have learnt when mashing out or sparging the slower the better. Too fast and you can induce channeling or a stuck sparge. Small batches seem to channel easier as well.
 

NzBrewerMatt

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Thanks for all your suggestions! I'm going to retry another batch tomorrow following as much of these points as I can. I also have a grain mill arriving tomorrow so fingers crossed this will help.

Lastly, check the gravity at a few steps of the process so you can target where you might be going wrong -
  • First runnings after the mash cycle
  • Gravity and volume before the boil
  • Gravity and volume after the boil (in the kettle)
  • Volume into the fermenter (which is what's used to determine brewhouse efficiency)
Once you have all the above come back to us and I'm sure you'll get a straight answer.
In regards to measuring each of the different stages, I have a refractometer (is calibrated) so thankfully I can do this easily. Is there a calculator that each of these can be put into (first runnings, gravity/volume before boil) that tells me if I'm going to hit my OG?

What I feel could be happening is when I'm transferring some of that first runnings into the boil kettle, I'm perhaps leaving some behind. This could be because I'm opening the valve up fully and letting it flow out quite quick. Is there a way to ensure all wort is collected?

I'll also try mashing with my pants off ;)
 

TheWiggman

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I don't batch sparge, but if it's sitting for 30 mins I don't think the rate of draining the mash tun will matter. If fly sparging however it's a completely different story.
Matt, check your refractometer against a hydrometer. They can be out of scale as well as incorrectly zeroed (think y = mx + b from back at high school). If you want to make up a solution, get out the scales.

A solution of 50g of table sugar in 500ml of water will give an SG of 1.051. If you mix that up you can check your refractometer with confidence.
 

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