Is Efficiency Related To Boil Size?

[Jye]

After having a chat with Ross last night about my poor efficiency (55%) it appears it could be due to my smaller boil volume, meaning I am using less sparge water.

Ross and I both batch sparge and get our grain cracked with the same mill, but my efficiency is 55% with a pre boil volume of about 30L where as Ross gets 75% with a pre boil volume of 40L.

If all the other batch spargers could post there grain size (kg), efficiency and pre boil volume for some recipes we can see if there is a trend here. I understand people get different efficiencies when doing a light (higher %) or heavy (lower %) so it would be good if you could post what efficiencies you got for them too.

Cheers :beer:

Grain - Efficiency - Boil volume

7, 55, 30

 

[warrenlw63]

As per my last batch. Batch sparged. :beerbang:

Grain 8.5kg - Efficiency 79% - Pre Boil Volume 50 Litres. Post boil 42-44 Litres.

Simple answer Jye. Get yourself a bigger pot.

Warren -

 

[Gough]

I boil 31 litres per batch and get 72-75% efficiency. Grain bill only impacts within that 3% range ie: heavier beers 72% lighter beers 75%. Batch sparging.

Shawn.

 

[Aaron]

My average figures worked out over the last few brews:


6kg, 74%, 31l

Perhaps your low efficiency has to do with other parts of your brewery. I don't claim to be the guru but I wouldn't of thought that boil volume alone would make that much of a difference.

 

[Jye]

Get yourself a bigger pot.

I can handle bigger boils and will increase my pre boil volume to see if there is a change next brew.

Keep them coming guys.

 

[KoNG]

Could the difference be in how much 'sparge' water is being used..? and therefore how much is actually making its way to the kettle.?

 

[pint of lager]

There are two sorts of efficiency.

1. Your mash tun efficiency. This measures how effectively you extract the wort sugars (sachaarides) into the boiler, preboil. This is mainly governed by when you stop sparging and the quality of your crush.

2. Your total brewhouse efficiency. This is how effective overall your system is at getting the sachaarides out of the grain and into the fermenter. This factors in wort that remains in the system and doesn't make it into the fermneter. Losses include wort remaining in the boiler, in the hot/coldbreak, in the hops and in the chiller.

I regularly get 90% fly sparging, 8 kg grain, preboil size 56 litres into the boiler. Then the overall efficiency drops off as wort is lost in the chiller and hot/cold break. One step I take great care with is getting rid of most of the hot and cold break by allowing the chilled wort to settle before racking it into the fermenter

Make sure you are comparing the same efficiency.

There has been talk recently of people using Powels malt getting lower efficciencies.

 

[pint of lager]

Meant to include the following.

If you are stopping sparging because your pot is full, then you may be stopping well before the runoff reaches sg 1.010, with corresponding lower extraction of sachaarides and lower efficiency.

 

[Gough]

My figures quoted above are 'total brewhouse efficiency'. My efficiency into the kettle is like POL has noted, much higher. FWIW I always quote 'brewhouse efficiency' when giving figures.

Shawn.

 

[Jye]

If you are stopping sparging because your pot is full, then you may be stopping well before the runoff reaches sg 1.010, with corresponding lower extraction of sachaarides and lower efficiency.

POL, Im batch sparging and referring to the brewhouse efficiency. I would like everyones figure to see if there is an increase in efficiency with and increase in litres of sparge water per kg of grain and is there a point of diminishing returns.

It is just very strange that my efficiency of 20% lower and the grain crush and method used is the same, with the only difference the amount of sparge water.

 

[Doc]

I notice an increase in efficiency on my system based on batch size. With my setup a bigger batch size means I must have a higher Liquor to Grist ratio so that I can get my volume into the boiler.
With a 25 litre batch size my ratio is ~2.8 litres/kg I get around 72-75% efficiency into the kettle.
With a 40 litre batch size on the same equip with a ration ~3.2 litres/kg I get around 82-88% efficiency into the kettle.

HTH,
Doc

 

[Ross]

Starting to look pretty conclusive Jye.... Bigger kettle mate ...

 

[Duff]

I have found that a higher water:grain ratio has helped. I recently brewed a couple of beers at 2.5L/kg, fly sparge and was lucky to hit 60%. It was Powells, but in fairness I think the crush wasn't as good so will try again with a finer crush before passing judgement on the grain. Last weekend I used Joe White for a Saison and Australian Ale, upped the ratio to 3L/kg and a finer crush, hit 84% for the Saison and 88% for the Australian Ale into the kettle. 20L into fermenter, Australian Ale used 4.87kg grain.

 

[Aaron]

Mine is also total brewhouse efficiency. I am averaging 74% with only 31l preboils. You should try some preboil measurements. This may help you track down at what stage you are having problems.

 

[bonk]

thats one thing i really need to sort out, my pre-boil volumes to help nail down my system figures, however since i usually mash in at approx 2.5L/kg and get around 70% i'll try and bump up to the ~3L mark and have a crack at that and report back on it as well.

cheers.

 

[Jye]

Hey bonk

Im not too concerned about the mash in ratio, I use 2.5 as well, but does more sparge water helping to rinse the grain.

I think my last post was a bit confusing when I said "litres of sparge water per kg of grain". This would work out to be 4.3 for 7kg of grain and a pre boil volume of 30L or 5.7 for a 40L pre boil volume. This is the ratio I would like to know and if an increase will result in increased efficiency.

Cheers

 

[shmick]

Just a thought...

The Lauter tun dead space remains constant no matter what batch size you do.

This forma a portion of the efficiency loss.
If you double the batch size you halve the % lost to this.

:chug:

 

[KoNG]

Hey bonk

Im not too concerned about the mash in ratio, I use 2.5 as well, but does more sparge water helping to rinse the grain.

I think my last post was a bit confusing when I said "litres of sparge water per kg of grain". This would work out to be 4.3 for 7kg of grain and a pre boil volume of 30L or 5.7 for a 40L pre boil volume. This is the ratio I would like to know and if an increase will result in increased efficiency.

Cheers

[post="95860"][/post]​

Jye,
i'm trying to follow all this for my own benifit as i have been having variable effeciency of late.
above are you stating that you would add 4.3 Litres/Kg grain for the sparge.?
has this accounted for dead space in the tun.?

 

[KoNG]

ooops, didnt see shmicks post... thats a good point.

 

[Aaron]

This is the ratio I would like to know and if an increase will result in increased efficiency.

[post="95860"][/post]​

So a good way to measure this is to take a measurement with a refractometer after sparging and prior to boiling. You can then check your mash efficiency. Then get the Ross to make the same measurements and calculations. You can now compare your mash efficiency. This will allow you to pin down at what stage of the process you are getting your reduction in efficiency compared to his.