Why is my efficiency so low? All grain brewing

[Simdop]

So I moved from BIAB to all grain brewing a year and a half ago or so. I was having fantastic success with my brews till recently when I changed my setup. My gravity readings seem too low and I'd love some help.

Some background, my system is a mash tun made out of a 50L stainless steel keg with a false bottom. I've got a tap welded in with a thread on the inside so that the false bottle is securely connected to the tap.

My kettle is another 50L stainless keg with two taps at the bottom welded in. Both have a thread on the inside. One has an elbow angled down, the other an elbow angled to the side.

This is the basic system that I had been using for a while with good results. However, I was gravity feeding from the mash tun into the kettle and sparging with a jug from my hot liquor tank. Due to space and height reasons I couldn't get a multi level gravity feed so I was struggling with moving things around. It got very frustrating.

So, enter a chugger pump, sparge coil, a cheap keg king pump and a cheap Chinese urn. I now heat the water in the urn to around 77, pump that into the sparge coil which then gently sprinkles the sparge water on top. I then use the chugger pump to transfer from the mash tun into the kettle. I also used it to whirl pool (using the aforementioned two taps and elbows).

The pumps made it much easier for me to work in the space I had and not struggle with lifting the kettle once full onto the burner and the like. However, my gravity readings for brews have been terrible since.

I did a pale ale with 5kg of pale malt and 500g of light crystal. It was a 23L batch which came out with an OG of 1038, which I thought was rather low?

I spoke to the guys at Riverside on a visit and they suggested that the pump could be causing problems pulling the wort out of the mash tun and into the kettle - pulling the liquid down the sides rather than through the mash. So I've introduced a transfer tank with has a pickup at the bottom for the pump. I now gravity feed from the mash tun and into the tank, I then use the pump to transfer the liquid from there into the kettle.

I also spent some time making a dip stick for the kettle so I can sparge to the right level. I'm ending up with a litre or so of trub left in the kettle and about 21L in the cube.

With those changes I've now done two brews.

One was an IPA. 8.5kg of pale, 500g of carapils and 500g of light crystal. I ended up with an OG of 1066 with 22L of water.
The other I've just done now. 4kg of pale, 500g of carapils and 150g of acidulated. My refractometer says a sample I took from the left over in kettle after cubing tells me that the OG will be about 1039.

This still seems rather low to me!

Other facts that may help:

- I used to use Absolute Homebrew in St Marys (NSW) for my grain till we had a bad business dealing. Now I use Country Brewer in Kingswood (NSW) for my grain but it is prepackaged ground.
- I moved from tap water to filtered tap water.
- I tried magnisum sulfate in my last brew to harden the water a little


Can anyone shed some light on what I might be doing wrong? I would love some help as I'm starting to get rather discouraged by my low OG's

 

[dave81]

How long do you sparge for?
How big is your false bottom in the mash tun?
Is it a herms , do you recurculate through a herms coil (sorry cant tell by the pics )
Or just have 3 vessels?

 

[Camo6]

Heaps of variables.

Could be the crush of the grain, channeling in the MT, mash PH etc.

Are you using software and if so what is your efficiency set to?

Have you measured the SG of your final runnings?

Tried an iodine test to check mash conversion?

What's your boil off rate/ pre boil SG/ post boil OG?

 

[MHB]

I just know we are going to get a chorus of Water Chemistry replies, I doubt that that is really the problem, Calcium is vital to get good consistent results and I would be looking at using Calcium Chloride and/or Calcium Sulphate in preference to Magnesium Sulphate if you want a good general purpose Ca salt mix go with 1 Cl to 2 SO4. always worth remembering that the potential for the grain is reported from a congress mash done in distilled water, so Zero salts.

The first place I would be looking is at my temperatures, if you are trusting that dial thermometer without having calibrated it there is a fair chance that it could be out. I think its vital to have one good laboratory grade thermometer that you trust and used it to benchmark all your other equipment.
Try an alternative malt supplier (or go and sort out your shit with Pat, I find he is approachable and if you have a problem at least talk it through with him) I am a little suspicious of pre-cracked grain.

Mark

 

[Simdop]

The false bottom of the mash tun. I believe its a 30cm one?

 

[seamad]

Agree with the variables above, if it's faulty fly sparging technique causing the problem try batch sparging next brew, if still low then start looking at grain, calcium salts etc.

 

[Simdop]

I just know we are going to get a chorus of Water Chemistry replies, I doubt that that is really the problem, Calcium is vital to get good consistent results and I would be looking at using Calcium Chloride and/or Calcium Sulphate in preference to Magnesium Sulphate if you want a good general purpose Ca salt mix go with 1 Cl to 2 SO4. always worth remembering that the potential for the grain is reported from a congress mash done in distilled water, so Zero salts.

The first place I would be looking is at my temperatures, if you are trusting that dial thermometer without having calibrated it there is a fair chance that it could be out. I think its vital to have one good laboratory grade thermometer that you trust and used it to benchmark all your other equipment.
Try an alternative malt supplier (or go and sort out your shit with Pat, I find he is approachable and if you have a problem at least talk it through with him) I am a little suspicious of pre-cracked grain.

Mark

Mark, I did some research just now and I realise I meant to get Calcium Sulphate not Magnsium. Picked up the wrong bag

I didn't quite follow what you were saying about the congress mash in distilled water?

How/what would you suggest to calibrate the temp gauge? If the mash temp is out by a few degrees will it really affect the final gravity that much?

For the record I did approach Pat however it wasn't resolved to a position that we were both happy about (I have a mate who manages a high profile craft beer bottle shop who I talked through the situation with and he doesn't think that my position was unreasonable). I could try a different grain supplier. Do those numbers seem rather low?

 

[Simdop]

Agree with the variables above, if it's faulty fly sparging technique causing the problem try batch sparging next brew, if still low then start looking at grain, calcium salts etc.

Faulty fly sparging? I was wondering if it would be a good idea to try batch sparging next time.

How much does the sparge temperature affect the extraction?

 

[Simdop]

How long do you sparge for?
How big is your false bottom in the mash tun?
Is it a herms , do you recurculate through a herms coil (sorry cant tell by the pics )
Or just have 3 vessels?

I've got a few marks on a dip stick that I used. I've figured out what my evaporation results at, so I've got a preboil mark that I sparge to if that makes sense?

It's not herms, its three separate vessels, I just use the coil for sparging.

 

[Simdop]

Heaps of variables.

Could be the crush of the grain, channeling in the MT, mash PH etc.

Are you using software and if so what is your efficiency set to?

Have you measured the SG of your final runnings?

Tried an iodine test to check mash conversion?

What's your boil off rate/ pre boil SG/ post boil OG?

I've been using BrewMate. I leave the efficiency set to the default of 70% however, i was on average hitting about 65 until i changed the setup to the pumps.

Keep in mind guys that until i changed it up a bit with the pumps everything was running really well (apart from the occasional burn and the hassle of moving stuff about!)

I haven't tried measuring the boil off rate. I only got the refractometer for Xmas so I'm still getting the hang of it. for todays brew it looked like preboil was about 1026 and post was 1038-9

 

[MHB]

All over the world maltsters use a standard test, from that they report the potential of the malt (usually about 80% for base malt), the colour and the boil colour, the protein content... and nearly all the other information we have on a COA (certificate of analysis). The COA gives us a fairly good idea of how the malt should preform. Here is a copy View attachment Congress Mash.PDF


"I did a pale ale with 5kg of pale malt and 500g of light crystal. It was a 23L batch which came out with an OG of 1038, which I thought was rather low?"

You used a total of 5.5Kg of malt. If we assume the potential of the grain bill was 77%, that means that if we preformed as well as the congress mash (i.e. 100% efficiency) we would get 4.23Kg of extract, You made a 23L batch and your losses were about 3L so your extract was dissolved in about 25L, means that if everything went perfectly your OG would have been around 18oP or 1.073.
If your OG was 1.039 you only got about 53% efficiency and yes that is very/unacceptably low.

I like Refractometers but they have to be used properly, be a good idea to check that it is calibrated, but first I would be looking at temperature, get a decent thermometer, not a cheap Chinese one I've seen them out by 200C, should only cost $10-15.

Put water in your vessel, heat to about mashing temperature, stir well and measure temperature, compare readings and adjust if needed, note that the thermometer will be either partial (76mm) or total immersion, if you use it wrong you could be 3 degrees out.
Mark

 

[Simdop]

All over the world maltsters use a standard test, from that they report the potential of the malt (usually about 80% for base malt), the colour and the boil colour, the protein content... and nearly all the other information we have on a COA (certificate of analysis). The COA gives us a fairly good idea of how the malt should preform. Here is a copy

Congress Mash.PDF


"I did a pale ale with 5kg of pale malt and 500g of light crystal. It was a 23L batch which came out with an OG of 1038, which I thought was rather low?"

You used a total of 5.5Kg of malt. If we assume the potential of the grain bill was 77%, that means that if we preformed as well as the congress mash (i.e. 100% efficiency) we would get 4.23Kg of extract, You made a 23L batch and your losses were about 3L so your extract was dissolved in about 25L, means that if everything went perfectly your OG would have been around 18oP or 1.073.
If your OG was 1.039 you only got about 53% efficiency and yes that is very/unacceptably low.

I like Refractometers but they have to be used properly, be a good idea to check that it is calibrated, but first I would be looking at temperature, get a decent thermometer, not a cheap Chinese one I've seen them out by 200C, should only cost $10-15.

Put water in your vessel, heat to about mashing temperature, stir well and measure temperature, compare readings and adjust if needed, note that the thermometer will be either partial (76mm) or total immersion, if you use it wrong you could be 3 degrees out.
Mark

Mark, I've got the thermometer below, is that the sort that you are referring to? The gauge is from Mash Master, I believe it is full immersion.

It sounds like my efficency is terrible :/ What would you expect for an average home brew system?

I followed the instructions that came with it for calibration?

If the thermometer below is fine, I'll try that for checking temperatures between it and the gauge. If not, what would you suggest in terms of brand and where to get one?

Also, with: " You made a 23L batch and your losses were about 3L so your extract was dissolved in about 25L". If the amount of water that it was dissolved in was higher say 27L but it still came out at 23L would that make any difference?

 

[MHB]

I cant tell you much about the thermometer you have, all the info is on the other side. It should tell you if its total or partial immersion or have a line where it should be immersed to. The mash master dial thermometers are OK, but they need to be calibrated regularly - against an accurate thermometer.
I generally expect around 80% efficiency, a little lower on high gravity beers, 90% is reasonably doable but you start to risk over extracting and getting tannins.

Yes if you change the amount of water the extract is dissolved in the answers change, I did some rough numbers based on a total of 25L at end of boil, if in fact you had 27 the efficiency would change by 2/27*100 ~ 7%, still a long way from good.
Mark

 

[contrarian]

Where are you taking the reading from? I BIAB but find that after a 70-90 minute mash the gravity always reads low unless I've given it a good stir.

If you're lucky it will be a simple measurement error that is easily resolved. Hope it is!

 

[Pokey]

Are your measurements only with the refractometer? Maybe it needs calibration

 

[Simdop]

I cant tell you much about the thermometer you have, all the info is on the other side. It should tell you if its total or partial immersion or have a line where it should be immersed to. The mash master dial thermometers are OK, but they need to be calibrated regularly - against an accurate thermometer.
I generally expect around 80% efficiency, a little lower on high gravity beers, 90% is reasonably doable but you start to risk over extracting and getting tannins.

Yes if you change the amount of water the extract is dissolved in the answers change, I did some rough numbers based on a total of 25L at end of boil, if in fact you had 27 the efficiency would change by 2/27*100 ~ 7%, still a long way from good.
Mark

Mark, what I was asking was if you start with 27 or you start with 25, but end up with 23 then it does that affect it at all? Surely it would not?

I'll try checking the temp gauges then if i can find a reliable one as a base.

Where are you taking the reading from? I BIAB but find that after a 70-90 minute mash the gravity always reads low unless I've given it a good stir.

If you're lucky it will be a simple measurement error that is easily resolved. Hope it is!

With the refractometer I've taken samples from the kettle pre boil and from the left overs in the kettle after cubing. But I've also been taking gravity readings when I pitch the yeast so the readings aren't the problem (it's pretty hard to get a hydrometer reading wrong?)

Are your measurements only with the refractometer? Maybe it needs calibration

Nah I've also been using the hydrometer as well. I followed the instructions for the refractometer for calibrating it so it should be okay?

 

[Mickcr250]

My money is on the grain, I had an efficiency problem for ages when I first started brewing and tried everything to fix it. Then one day I got some grain from craftbrewer and bam my efficiency jumped up to 75%.

 

[contrarian]

Yep, highly likely that if everyhting else is the same except the source of the grain that it might be the culprit.