Is Efficiency Related To Boil Size?

[sosman]

Figures below reflect my mash efficiency. My overall efficiency depends quite a bit on how much hops I add to the recipe, more hops means I leave more in the kettle.

                    grain.mass efficiency pre_boil.vol

belgian01b               6.30       0.83           33

marzen                     NA         NA           NA

OzPaleAle                3.80       0.89           34

OzWheat                  4.50       0.87           34

OzWheat_2                5.00       0.85           33

steam                      NA         NA           NA

Stout02                  5.54       0.74           33

sweetStout               4.85       0.83           35

WA_APA                     NA         NA           NA

WA_APA_4_HopHead         5.33       0.91           34

WA_APA_5-02              5.33       0.85           34

WA_APA_5                 5.33       0.84           35

WA_APA_6-01              4.53       0.86           34

WA_APA_7-01              5.13       0.84           35

WA_APA_more_malt 2       5.33       0.88           34

WA_APA_more_malt 3       5.42         NA           34

WA_APA_more_malt           NA         NA           NA

Wheat_3                  3.80       0.87           35

This particular data set has no (linear) correlation between pre boil volume and efficiency

As has been pointed out, your fixed losses are more significant with smaller batches. Mashtun dead volume, kettle dead volume, chiller dead volume. Also you typically have dead volume in your fermenter.

If you measure the SG of your last runnings, you can calculate how much sugar is left in the mashtun. You need to know your water volume (dead volume + loss to grain) and make an assumption regarding conversion efficiency.

Also when batch sparging, the ratio of mash runoff to sparge runnoff affects efficiency, I have not crunched the numbers but others that have state that the optimal efficiency is achieved (all else being equal) when both runoff volumes are equal.

 

[bonk]

jye, ah gotcha...

the one i thing i need to do is stop being lazy and build a dip-stick of some sort so i can measure my pre boil volume and attempt to figure out my % boil off. not sure if big d has the same problem, but i usually get around 25+% boil off, thats in the 40L bucket-o-doom.


sos, so volume in should be volume out? say if i collect 30L in the boiler, 30L should have gone in as sparge water?

 

[sosman]

sos, so volume in should be volume out? say if i collect 30L in the boiler, 30L should have gone in as sparge water?

[post="95978"][/post]​

No. I work through an example at http://brewiki.org/BatchSparge but it works something like this for me:

preboil_vol = mash_water_vol + sparge_water_vol + loss_to_grain + mashtun_dead_vol

mash_runnoff ~= sparge_runoff ~= preboil_vol/2

=> mash_water_vol = pre_boil/2 + loss_to_grain + mashtun_dead_vol
=> sparge_water_vol = pre_boil/2

If I do a mashout, that addition is just incorporated into mash_water_vol.

Of course I use Brewsta to work most of it out for me

Some points I prepared earlier:

 

[warrenlw63]

Sosman.

You don't do those on-screen stats at the cricket by any chance?

Warren -

 

[bonk]

Hi Sos,

thats what i thought and try to aim for (process wise)

thanks

 

[Steve]

Interesting thread Jye as im on the eve of my first partial - did anything eventuate? Did getting a bigger pot and more sparge water make a difference? One question im hoping someone can tell me as I cant find it after searching. How do you work out your efficiency? Dumb question I know - sorry.
Cheers
Steve

 

[Jye]

I ended up cutting a bigger opening in the top of my keg (kettle) which increased my evaporation rate. This allows me to sparge with a few more litres and has raised my efficiency to about 60-65%... woo-hoo <_<

I would still like to get better efficiency but Im not to worried about it, I get a great deal on my grain and it still makes beer in the end :chug:

 

[Ducatiboy stu]

I batch sparge

I mash at 2.5:1, and sparg at 2.5:1

I usually get about 80% total eff, using pre-cracked grains stored in the freezer.

I have noticed that using sparge water at just below 80* gives better eff then water at 70*

I end up with 29 in the kettle and 22ltrs in the ferm.

Hopefully when I get my mill sorted fully ( The Tony Mill ) and get into fresh cracked grain, my eff will increase


NOTE:- Drinking beer when mashing can affect effiency h34r:

 

[tangent]

NOTE:- Drinking beer when mashing can affect effiency

aaaaahhh, so that's why my numbers are all over the place!