How to measure mash efficiency

[BrewingWisdom]

Hi
What is the method of measuring preboil mash efficiency?? Like how much sugars I extracted from my mash.
I am going to use to BIAB method.

 

[VikeMan]

Mash Efficiency is the percentage of the total possible (theoretical) sugars and dextrins from
the mash that actually make it to the boil kettle. To compute mash efficiency, you need the following data:

- The amounts (in pounds) of each grain used and their extract potentials in Points per Pound per Gallon (PPG)
- The volume of wort that made it to the kettle
- The gravity of the wort that made it to the kettle

For example, suppose we have 10 pounds of a 38 PPG malt. The total possible “Points” would be:
(10 Pounds x 38 Points per Pound) = 380 Points

Also suppose we got 6 gallons of wort into the kettle and it had a gravity of 1.048. We can say that the Points that made it to the kettle are:
48 Points per Gallon x 6 Gallons = 288 Points

So we have…
•380 Points theoretical Maximum
•288 Points actual to the Boil Kettle
Now we can compute our Mash Efficiency:
(Points in the Kettle) / (Total Possible Points)
288 Points / 380 Points = 75.8% Mash Efficiency

 

[BrewingWisdom]

Mash Efficiency is the percentage of the total possible (theoretical) sugars and dextrins from
the mash that actually make it to the boil kettle. To compute mash efficiency, you need the following data:

- The amounts (in pounds) of each grain used and their extract potentials in Points per Pound per Gallon (PPG)
- The volume of wort that made it to the kettle
- The gravity of the wort that made it to the kettle

For example, suppose we have 10 pounds of a 38 PPG malt. The total possible “Points” would be:
(10 Pounds x 38 Points per Pound) = 380 Points

Also suppose we got 6 gallons of wort into the kettle and it had a gravity of 1.048. We can say that the Points that made it to the kettle are:
48 Points per Gallon x 6 Gallons = 288 Points

So we have…
•380 Points theoretical Maximum
•288 Points actual to the Boil Kettle
Now we can compute our Mash Efficiency:
(Points in the Kettle) / (Total Possible Points)
288 Points / 380 Points = 75.8% Mash Efficiency

But how to calculate PPG,s?
I've seen a video where the hydrometer was dipped in a pre boil wort to measure the gravity.According to him this pre boil sample was for measuring the mash efficiency. Then again this gravity test was conducted post boil and last and finally when the fermentation was complete . I know post boil and final gravity determines our ABV. But in all these three samples how the preboil sample plays its part in determining the mash efficiency?

 

[VikeMan]

But how to calculate PPG,s?

The easy way is to let brewing software do it for you. If you want to do it manually (and proibably more accurately), you need some information from the maltster, i.e. the "Dry Basis Fine Grind" percentage and the moisture percentage.

Example:

DBFG = 80%
Moisture = 4%

PPG = DBFG x (1 - Moisture) x 46.21 PPG
PPG = 80% x (1 - 4%) x 46.21 PPG = 35.5 PPG

I've seen a video where the hydrometer was dipped in a pre boil wort to measure the gravity.According to him this pre boil sample was for measuring the mash efficiency.

Yes, but you also need to know the volume in the kettle and the total theoretical "points" in the grain bill.

According to him this pre boil sample was for measuring the mash efficiency. Then again this gravity test was conducted post boil and last and finally when the fermentation was complete . I know post boil and final gravity determines our ABV. But in all these three samples how the preboil sample plays its part in determining the mash efficiency?

You can use either the pre-boil or post-boil gravity in your mash efficiency calculation. Just be sure to use the corresponding volume of wort. Either way, you'll get the same answer, because when you boil, the same total "points" in the kettle become more concentrated (i.e. the wort gravity increases) in the smaller volume.

 

[CascadesBrewer]

What is the method of measuring preboil mash efficiency?

I agree with the suggestion to use software to help with the calculations. For example, I measured a Post-Mash (same as Pre-Boil) reading of 1.057 (1 point lower than the predicted) and a volume of 6.5 gallons (matched my target) and BeerSmith calculated a Mash Efficiency of 75.1%.

I've seen a video where the hydrometer was dipped in a pre boil wort to measure the gravity.

Note that efficiency calculations are only as accurate as the gravity and volume measurements. The easiest tool for brew day gravity measurements is a refractometer. To take a hydrometer reading, you really need to cool down the sample to get a reasonably accurate measurement. There are some hydrometers that are calibrated around mash temps, but a standard hydrometer is often calibrated for a 60F reading. You also have to be able to get an accurate volume reading.