mash effeciency

how do you calculate how efficient your mashing is? i used the following grain bill, and my pre-boil gravity was 1.052

american pale ale

5 lbs domestic 2-row
5 lbs pilsner
.5 lbs carapils
.5 lbs crystal 40

did a step mash with 1/2 hour rests at 122 & 150 and a 15 minute rest at 170

oh and we pulled about 6 gallons and some change

its simple: take your actuall and divide by your theoretical

ex. 1.050 (actuall) divided by 1.070 (theoretical) = 50/70 = .71 or 71 percent

if you know your efficiency then you can take your theoretical and multiply by your efficiency and get your actuall...ex. 1.070 (theo) multiplied by .71 (percent)=50 or 1.050

theoritical being if i were to get all the fermentables out of the grain?

to calculate your theoretical do this:

5 lbs 2-row times 35 = 175
5 lbs pilsner times 36 = 180
.5 lbs crystal times 24 = 12
.5 lbs crystal times 24 = 12

added up =379
divide by 5 (gallons) = 75.8 or 1.078(theoretical)
times 78 by 1.052(52)= 69 or 69 percent

whatever lbs grain times these numbers : 2-row 35
pilsner 36
crystal 24
d.m.e 45
l.m.e. 36
sugar 40
add these numbers and divide by 5 = theoretical o.g. (100 percent efficiency)

subwyking said:

theoritical being if i were to get all the fermentables out of the grain?

Click to expand...

my info is straight out of Dave Miller's book "homebrewers guide" or "everything you need to know to make great tasting beer"

Do you have a post boil gravity?

Your efficiency might be higher than that. how long did you boil it for?

did a 90 minute boil. and in our haste we did not take a gravity reading then

Alright guys correct me if I am wrong here.

But boiling for 90 minutes means he lost 1.5 gallons, putting is starting volume at 7.5 gallons @ 1.052.

Using the End Gravity=Beg Volume * Beg Gravity / End Volume formula 7.5* .052 / 6 gives us 1.065 as a starting gravity. Correct?

Now using the formula from Cgravier
"added up =379
divide by 5 (gallons) = 75.8 or 1.078(theoretical)
times 78 by 1.052(52)= 69 or 69 percent"

379/6(gallons) = 63 or 1.063 (theretical max) which is lower than than what we have here.

So I checked this calculator http://www.texanbrew.com/tbcalcs/index.php and the numbers are different for the grains. Under pilsener I have a theretic max of 1.037, 2-row is 1.039, and crystal I picked a 10 L and it comes out to 1.035. Using the figures above I have you at 94% efficiancy.

Someone please check my figures.

Thanks

George

Oh,

Forgot to mention, did you correct your reading for the temperature of your hydrometer? (what temp did you test and what is it rated for)?

Is the hydrometer calibrated? (put in distilled water at temperature listed on hydrometer. should read 1.000)

yeah i adjusted for temp. and ive also checked the hydrometer before and its right on the money. so based off of your guys calculations im at either 70% or 94%. im thinking that this is pretty good for just our second AG batch and a homemade grain mill.

id say for beginning ag 70% is pretty damn good. i get 70 percent pretty consistantly, and i do a "fly" mash.i doubt your geting 94% but i could be wrong.as far as the descrepincy (sic) in the numbers iwas going from memory. Although these numbers do work for me.
thats why they invented the hydrometer anyway.

cool thanks alot. i guess next time ill have to make sure to take a post boil hydro reading. when is the best time to do it? im assuming after it cools to avoid a shattered hydro in the beer.

You could do it in your fermenter before pitching yeast which should be at a reasonable temperature. I like to know before I start boiling where I'm at (if something went drastically wrong I can add extract to make up) so I use one of those cylindrical sample tubes which will float a hydrometer with a minimum of wort. These will cool super fast in a glass of ice water.

ah, thanks for the tip. ill keep that in mind for the next brew day.