Why is my efficiency so low? Can someone explain my efficiency? I thought I understood efficiency. These statements are just some examples of the many threads relating to efficiency that I have seen on HomeBrewTalk. It would seem the forum is replete with individuals scratching their noodles in an effort to solve a conundrum their brewing data has presented. Fortunately, there are many helpful members who are ready, willing, and able to crunch the numbers, point out possible errors, and in many instances solve the riddle.
The purpose of this article is not to explore brewing-science's formulae and mathematics, but to illustrate some simple steps involved in the collection and interpretation of useful brewing data. Many homebrewers, myself included, use brewing software to crunch the numbers and calculate efficiencies. Through accurate data collection and analysis, brewers can more easily localize problems with their equipment or methods and find effective solutions. Lets look at two important numbers, mash efficiency and brewhouse efficiency, and explore what each of them means.
Mash Efficiency
This is a measure of how effective your methods are at extracting the starches from the grains, converting those starches to sugars, and getting the resultant sugars out of the mash-tun and into your boil-kettle. In other words, how effective you are at getting the available sugars into your kettle. Its no more complicated than that. To calculate mash efficiency we need to know three things.
How Much Sugar Do You Get From Your Grain
Maximum Potential Gravity
Every grain has a variety of descriptive numbers associated with it. One of these is its potential gravity and is measured in points per pound per gallon (PPG). This is the theoretical specific gravity of a gallon of wort containing 100% of the potential sugars in one pound of the grain. A grain-bills potential gravity is the sum of the gravity points available from each grain-type. Unless you perform your own grain analysis, this number is dependent on the accuracy of two things; the malsters grain data and weight of the grain-bill. Accurately weighing each grain-type is therefore very important.
Specific Gravity
A representative sample of the sweet-wort is taken from the kettle, cooled to the calibration temperature of the measuring device, and its specific-gravity measured. Hydrometers or refractometers can be used. I favor narrow-range hydrometers for their ease of use. Both the sample and hydrometer are cooled prior to taking a reading. If only the sample is cooled, adding a room-temperature hydrometer will induce a temperature change and small measurement error.
Potential Gravity Measured In Points Per Pound Per Gallon
Volume
The volume of sweet-wort prior to the boil can be measured in a variety of ways. A calibrated dowel, ruler or sight-glass are popular methods. Another approach is to etch volume-markings directly onto the kettle. This is the method I chose. Owing to the high temperatures (~170F) of the sweet-wort, pre-boil measurements must be corrected to account for volumetric shrinkage to the hydrometers calibration point. This correction, approximately a 2.5% reduction in volume from pre-boil temperatures is not automatically made by the popular brewing software I use.
Why is it important to measure mash efficiency?
Multiple enzyme mediated chemical reactions occur in a mash. These reactions produce the fermentable sugars and other compounds responsible for giving a beer its signature characteristics. Knowing how good a job we did at mashing (getting the sugars into our boil-kettle), can highlight procedural problems before and during the mash. Factors negatively impacting the efficacy and efficiency of a mash include:
After mashing and lautering, the wort is heated and boiling ensues with or without corrective measures. If mash efficiency is not in-line with the brewers objective, such corrections can include an addition of malt extract or an adjustment to the planned boil duration. This is a completely different, albeit related topic, beyond the scope of this article. When the boil is complete, the wort is cooled and transferred to the fermentor. Brewhouse efficiency can now be calculated.
Grain Crush, Mash Thickness And Temperature Contribute To Mash Efficiency
Brewhouse Efficiency
This is a measure of how effective your entire brewing process is. What portion of the total potential sugars made it into the fermentor. It can never be greater than your mash efficiency and is affected by volume losses during and after the mash. To calculate brewhouse efficiency we again, need to know three things.
Grain Potential, Wort Gravity And Fermentor Volume Are Used To Calculate Brewhouse Efficiency
Maximum Potential Gravity
This is the same measurement as previously calculated. It is based on the malsters data and accurate weighings of the various grain-types
Original Gravity
After the boil a representative sample of the wort is taken from the kettle or the fermentor. The sample is prepared in the same manner as before, allowing accurate measurement of the original gravity.
Volume
The volume of wort transferred to the fermentor is easily measured using calibrated markings on the fermentor. I ferment my beer in glass carboys and added etched volume-markings to them. Accurate markings eliminate any guesswork.
Really Get To Know Your Volumes
Why is it important to measure brewhouse efficiency?
Monitoring and maintaining a high brewhouse efficiency is extremely important for commercial breweries as it significantly impacts their overhead costs and bottom line. Efficiency related cost savings are minimal on the homebrewing scale. I would argue however, that there are important, non-cost related benefits to developing more efficient brewing practices.
Knowing how good a job was done at getting the sugars into our fermentor enables the brewer to more accurately formulate recipes and water volume requirements at each stage of the brewing process. Assuming mash efficiency is known, the value can also highlight volume losses after the mash and areas where ones methods could be improved. Factors negatively impacting brewhouse efficiency include:
Take And Record Accurate Measurements
Unlike the astronauts in The Simpsons you dont need to be "a mathematician, a different kind of mathematician [or] a statistician", but you do need to take accurate measurements. Consistent and predictable efficiency better allows us to craft beers with intended characteristics, not ones dictated by inaccuracies inherent in our homebrewery. Isn't that a worthy goal?
Brewhouse Efficiency Calculations Aid In Brewing Consistency
The calculations involved in assessing brewing efficiency are not complex. Nonetheless, there are many beneficial reasons for using some form of brewing-software. There are lots of great options from which to choose. Many, like BrewersFriend.com are available for free.
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The purpose of this article is not to explore brewing-science's formulae and mathematics, but to illustrate some simple steps involved in the collection and interpretation of useful brewing data. Many homebrewers, myself included, use brewing software to crunch the numbers and calculate efficiencies. Through accurate data collection and analysis, brewers can more easily localize problems with their equipment or methods and find effective solutions. Lets look at two important numbers, mash efficiency and brewhouse efficiency, and explore what each of them means.
Mash Efficiency
This is a measure of how effective your methods are at extracting the starches from the grains, converting those starches to sugars, and getting the resultant sugars out of the mash-tun and into your boil-kettle. In other words, how effective you are at getting the available sugars into your kettle. Its no more complicated than that. To calculate mash efficiency we need to know three things.
- The estimated maximum potential gravity points in the grain-bill.
- The specific-gravity of the sweet-wort
- The pre-boil volume of sweet-wort in the boil-kettle
How Much Sugar Do You Get From Your Grain
Maximum Potential Gravity
Every grain has a variety of descriptive numbers associated with it. One of these is its potential gravity and is measured in points per pound per gallon (PPG). This is the theoretical specific gravity of a gallon of wort containing 100% of the potential sugars in one pound of the grain. A grain-bills potential gravity is the sum of the gravity points available from each grain-type. Unless you perform your own grain analysis, this number is dependent on the accuracy of two things; the malsters grain data and weight of the grain-bill. Accurately weighing each grain-type is therefore very important.
Specific Gravity
A representative sample of the sweet-wort is taken from the kettle, cooled to the calibration temperature of the measuring device, and its specific-gravity measured. Hydrometers or refractometers can be used. I favor narrow-range hydrometers for their ease of use. Both the sample and hydrometer are cooled prior to taking a reading. If only the sample is cooled, adding a room-temperature hydrometer will induce a temperature change and small measurement error.
Potential Gravity Measured In Points Per Pound Per Gallon
Volume
The volume of sweet-wort prior to the boil can be measured in a variety of ways. A calibrated dowel, ruler or sight-glass are popular methods. Another approach is to etch volume-markings directly onto the kettle. This is the method I chose. Owing to the high temperatures (~170F) of the sweet-wort, pre-boil measurements must be corrected to account for volumetric shrinkage to the hydrometers calibration point. This correction, approximately a 2.5% reduction in volume from pre-boil temperatures is not automatically made by the popular brewing software I use.
Why is it important to measure mash efficiency?
Multiple enzyme mediated chemical reactions occur in a mash. These reactions produce the fermentable sugars and other compounds responsible for giving a beer its signature characteristics. Knowing how good a job we did at mashing (getting the sugars into our boil-kettle), can highlight procedural problems before and during the mash. Factors negatively impacting the efficacy and efficiency of a mash include:
- Poorly crushed grain
- An overly thick or gelatinous mash consistency
- Excessively low or high mash temperatures
- A large mash-tun dead-space
- Ineffective sparging methods
- Poor management of mash pH*
After mashing and lautering, the wort is heated and boiling ensues with or without corrective measures. If mash efficiency is not in-line with the brewers objective, such corrections can include an addition of malt extract or an adjustment to the planned boil duration. This is a completely different, albeit related topic, beyond the scope of this article. When the boil is complete, the wort is cooled and transferred to the fermentor. Brewhouse efficiency can now be calculated.
Grain Crush, Mash Thickness And Temperature Contribute To Mash Efficiency
Brewhouse Efficiency
This is a measure of how effective your entire brewing process is. What portion of the total potential sugars made it into the fermentor. It can never be greater than your mash efficiency and is affected by volume losses during and after the mash. To calculate brewhouse efficiency we again, need to know three things.
- The estimated maximum potential gravity points in the grain-bill.
- The original-gravity of the wort (OG)
- The volume of wort in the fermentor
Grain Potential, Wort Gravity And Fermentor Volume Are Used To Calculate Brewhouse Efficiency
Maximum Potential Gravity
This is the same measurement as previously calculated. It is based on the malsters data and accurate weighings of the various grain-types
Original Gravity
After the boil a representative sample of the wort is taken from the kettle or the fermentor. The sample is prepared in the same manner as before, allowing accurate measurement of the original gravity.
Volume
The volume of wort transferred to the fermentor is easily measured using calibrated markings on the fermentor. I ferment my beer in glass carboys and added etched volume-markings to them. Accurate markings eliminate any guesswork.
Really Get To Know Your Volumes
Why is it important to measure brewhouse efficiency?
Monitoring and maintaining a high brewhouse efficiency is extremely important for commercial breweries as it significantly impacts their overhead costs and bottom line. Efficiency related cost savings are minimal on the homebrewing scale. I would argue however, that there are important, non-cost related benefits to developing more efficient brewing practices.
Knowing how good a job was done at getting the sugars into our fermentor enables the brewer to more accurately formulate recipes and water volume requirements at each stage of the brewing process. Assuming mash efficiency is known, the value can also highlight volume losses after the mash and areas where ones methods could be improved. Factors negatively impacting brewhouse efficiency include:
- Mash efficiency (brewhouse efficiency can never exceed this number)
- Spilled wort
- Dead-space in the kettle, chiller, and hoses
- Wort absorbed by hops
- Kettle-trub
Take And Record Accurate Measurements
Unlike the astronauts in The Simpsons you dont need to be "a mathematician, a different kind of mathematician [or] a statistician", but you do need to take accurate measurements. Consistent and predictable efficiency better allows us to craft beers with intended characteristics, not ones dictated by inaccuracies inherent in our homebrewery. Isn't that a worthy goal?
Brewhouse Efficiency Calculations Aid In Brewing Consistency
The calculations involved in assessing brewing efficiency are not complex. Nonetheless, there are many beneficial reasons for using some form of brewing-software. There are lots of great options from which to choose. Many, like BrewersFriend.com are available for free.
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