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- Thread starter redrocker652002
- Start date

Gravity points may be the hidden (and some what abstract) concepts.

- Gravity points are the amount of fermentable "stuff" in the wort.
- Gravity points are constant. Specific gravity changes based on wort volume.

Grains have a maximum potential PPG. Base malts are often 36 PPG. If efficiency were 100%, a pound of base malt would yield 36 gravity points. 36 gravity points in 5 gal of water is roughly SG 7.

At 100% efficiency the grain bill creates 384 gravity points

- 10 lb Extra Pale @ 36 PPG = 360 gravity points
- .75 lb Crystal 15 @ 32 PPG ) = 24 gravity points
*PPG will vary slightly based on brand of malt.*

250 / 384 = 65%

There's conversion efficiency and there's also mash efficiency which multiplies conversion efficiency with lauter efficiency. Then there's brewhouse efficiency, a whole other thing. Best to be specific about which one you're talking (or reading) about when.

You'll want fairly accurate volumetric data. The scale on the side of most kettles with 1/2 or 1/4G gradations is not accurate enough for very useful efficiency data. All volumes corrected to room temp.

You'll want fairly accurate volumetric data. The scale on the side of most kettles with 1/2 or 1/4G gradations is not accurate enough for very useful efficiency data. All volumes corrected to room temp.

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Over time I gathered really good information about a few dozen batches. Some high gravity, some low, many medium. Now, I can trust my recipe predictions to the point that as I get near the boil the surface of the FWH cap just touches the top edge of the kettle. My pre-boil volumes are spot on, within a couple

Again, I don't stress about the numbers. I gather them, crunch them, and use them so I don't have to. The beer in the kettle is the beer I designed in software. That's not important to many brewers.

The only people that worry about it are those who don't get anywhere near their expected OG.

Published recipes are often standardized on certain measurements (volumes, efficiencies, ...). For example, BYO Recipe Standardization.

Also, this BYO article (link, from 2005) may be of interest.

Also, this BYO article (link, from 2005) may be of interest.

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So far, since my return to brewing, I've ended up with one batch that was slightly undersized, for reasons I still don't know. Other than that, the wort is always at or above the target OG, and if it's over, I just dump water into the machine until I get the figure I want. I have ended up with more than 5 gallons of wort a time or two. I suppose this has some small effect on the bitterness, since the boil is finished, but I'm sure I can't tell the difference between 30 IBU and 33.

I don't know if I'm doing it wrong or what. I like the beer, though.

I don't know if I'm doing it wrong or what.

Numbers would help answer that question.

I like the beer, though.

If the variances and unpredictability of your process and product don't bother you, carry on!

I see it differently - but this the wrong place to discuss it. Curious? start a new topic.Seems like brewing always gets more complicated; never less.

We use the efficiency concept in reverse when designing a recipe to achieve a targeted OG. Let's go back to our Short Stout example.

To produce a 1.050 wort, how much malt will we need?

- First, we need to assume an anticipated yield (e.g. 30 ppg), for the recipe volume (e.g. 5 gallons).
- Then we multiply the target gravity (50) by the recipe volume (5) to get the total amount of sugar. 5 x 50 = 250 pts.
- Dividing the total points by our anticipated yield (30 ppg) gives the pounds of malt required. 250 / 30 = 8.3 lbs. (I generally round up to the nearest half pound, i.e. 8.5)
- So, 8.5 lbs. of malt will give us our target OG in 5 gallons. Using the malt values for 85% Efficiency in Table 9, we can figure out how much of each malt to use to make up our recipe.

Malts | OG based on PPG (85%) |

6.5 lbs. of 2 Row | 31 x 6.5 / 5 = 40.3 |

0.5 lb. of Chocolate Malt | 24 x .5 / 5 = 2.4 |

0.5 lb. of Crystal 60 | 29 x .5 / 5 = 2.9 |

0.5 lb. of Dextrin Malt | 28 x .5 / 5 = 2.8 |

0.5 lb. of Roast Barley | 22 x .5 / 5 = 2.2 |

8.5 lbs. total | 50.6 points total |

6 gallons of 1.042 (250 pts/6g) or

7 gallons of 1.036 (250 pts/7g)

So, when planning to brew with grain, you need to be able to figure how much malt to use if you are going to collect 6-7 gallons of wort that will boil down to 5 gallons at a target OG. (Actually you need 5.5 gallons if you plan for fermentation losses from the hops and trub.) These considerations are taken into account in Chapter 19 - Designing Recipes.

@BeerHolic: What you copied from the web site explains how to use efficiency to estimate OG.

OP wants to know how to calculate efficiency for OPs system.

*eta:* ... and yes, both calculating efficiency(s) and estimating OG be done with recipe software. What may missing from recipe software is the concept of "gravity points". What may "obscured" by recipe software is PPG for malts.

The calculations are not complex, although the equations do include 'units of measure' .

OP wants to know how to calculate efficiency for OPs system.

The calculations are not complex, although the equations do include 'units of measure' .

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Oops, my bad.@BeerHolic: What you copied from the web site explains how to use efficiency to estimate OG.

OP wants to know how to calculate efficiency for OPs system.

eta:... and yes, both calculating efficiency(s) and estimating OG be done with recipe software. What may missing from recipe software is the concept of "gravity points". What may "obscured" by recipe software is PPG for malts.

The calculations are not complex, although the equations do include 'units of measure' .

You did actually answer what was asked.

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No worries; I wanted to help OP minimize the amount of stuff that OP needs to read to answer OPs question.Oops, my bad.

This actually helps a lot. It gives me a base to work with thank you. I am guessing the numbers may change if the system efficiency is different though, right? Say I am only at 65%, would the numbers change?

Planning Malt Quantities for a Recipe

We use the efficiency concept in reverse when designing a recipe to achieve a targeted OG. Let's go back to our Short Stout example.

To produce a 1.050 wort, how much malt will we need?

- First, we need to assume an anticipated yield (e.g. 30 ppg), for the recipe volume (e.g. 5 gallons).
- Then we multiply the target gravity (50) by the recipe volume (5) to get the total amount of sugar. 5 x 50 = 250 pts.
- Dividing the total points by our anticipated yield (30 ppg) gives the pounds of malt required. 250 / 30 = 8.3 lbs. (I generally round up to the nearest half pound, i.e. 8.5)
- So, 8.5 lbs. of malt will give us our target OG in 5 gallons. Using the malt values for 85% Efficiency in Table 9, we can figure out how much of each malt to use to make up our recipe.
Remember though that this is the post-boil gravity. When you are collecting your wort and are wondering if you have enough, you need to ratio the measured gravity by the amount of wort you have collected to see if you will hit your target after the boil. For instance, to have 5 gallons of 1.050 wort after boiling, you would need (at least):

Malts OG based on PPG (85%) 6.5 lbs. of 2 Row 31 x 6.5 / 5 = 40.3 0.5 lb. of Chocolate Malt 24 x .5 / 5 = 2.4 0.5 lb. of Crystal 60 29 x .5 / 5 = 2.9 0.5 lb. of Dextrin Malt 28 x .5 / 5 = 2.8 0.5 lb. of Roast Barley 22 x .5 / 5 = 2.2 8.5 lbs. total 50.6 points total

6 gallons of 1.042 (250 pts/6g) or

7 gallons of 1.036 (250 pts/7g)

So, when planning to brew with grain, you need to be able to figure how much malt to use if you are going to collect 6-7 gallons of wort that will boil down to 5 gallons at a target OG. (Actually you need 5.5 gallons if you plan for fermentation losses from the hops and trub.) These considerations are taken into account in Chapter 19 - Designing Recipes.

OK, so I am confused. I added my fermentables and how much into the calculator. It gives you the list of which companies and which grains, so I did that as well. 5 gallons in the fermentor and it gives me a efficiency of about 70%. So, I am guessing, and just kinda thinking out loud, I can figure about 65 to 70% when I am building or scaling my recipes to the original recipe I have? This is fun, because I dig the numbers and reasoning to why. Thanks to all who had input. I appreciate it. Rock On!!!!!!!Published recipes are often standardized on certain measurements (volumes, efficiencies, ...). For example, BYO Recipe Standardization.

Also, this BYO article (link, from 2005) may be of interest.

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If you want to look deeper into the differences in the calculations, what were the PPM values for each of the malts in the calculator? If I change the values in #2 from 36 & 32 to 35 & 30, I get roughly 67%.it gives me a efficiency of about 70%.

That will be a good starting point for the next recipe.I can figure about 65 to 70% when I am building or scaling my recipes to the original recipe I have?

I agree. In school, I never liked story problem math ("Johny has three apples, Suzie has six, ... ?"). Then I learned to home brew!This is fun, because I dig the numbers and reasoning to why.

That would be a good suggestion. I will have to look into that again and see. I am guessing the number is listed in the product page in MoreBeer or some of those places?If you want to look deeper into the differences in the calculations, what were the PPM values for each of the malts in the calculator? If I change the values in #2 from 36 & 32 to 35 & 30, I get roughly 67%.

That will be a good starting point for the next recipe.

I agree. In school, I never liked story problem math ("Johny has three apples, Suzie has six, ... ?"). Then I learned to home brew!

5 gallons in the fermentor and it gives me a efficiency of about 70%

What kind of efficiency?

You really do want to separate the various efficiencies out for best understanding of your system/process and how recipes interact with them.

How you adjust for lower than typical mash efficiency is not the same as how you adjust for lower than typical brewhouse efficiency. If it's lauter efficiency that's the issue, you very well may just accept it, if it's consistent. If you find your conversion efficiency is rather low (<~95%), you'll likely want to fix it.

In the end, you'll get to the point where the source recipe's water volumes and grain weights don't concern you at all. You'll see a recipe and take its grist (by %) and OG. Exactly how much water and grain to use will be derived by your software using actual observed and measured system stats such as grain absorption, transfer losses, boil-off rate, etc. The recipe gives you the goal for the wort in the fermenter and how the author got there on their system. With understanding of what's under the hood of 'efficiency', you'll have the tools to get to the end goal

Conversion efficiency

Lauter efficiency

Mash efficiency

Brewhouse efficiency

Each type of efficiency provides very useful information about very different parts of your brewday. Brewhouse arguably being the least useful.

It's a good place to start looking. Occasionally the number can be found product information sheets (or calculated from data in those sheets).I will have to look into that again and see. I am guessing the number is listed in the product page in MoreBeer or some of those places?

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1. Efficiency is most influenced by the quality of the crush. If you don't own the mill, don't expect high efficiency nor should you expect consistent efficiency.

2. Sparging will increase efficiency but not by a huge amount. If the crush is bad, sparging will not overcome the deficiency.

3. If the crush is poor, a longer mash may be needed to get closer to complete conversion.

4. Any wort left in the boil kettle reduces efficiency. Trying to leave the trub behind when you transfer also leaves behind wort.

5. Efficiency isn't very critical in home brewing as you can make up poor efficiency by adding only a small amount of extra base malt.

Consistent efficiency is more important than the percentage.I came out with about 68% brewhouse efficiency I think it was. I will check it again.

If/when you decide to improve the percentage, the measurements that @DBhomebrew mentioned can be helpful. You mentioned "dunk sparge" which suggests you are BIABing - if so, the places to measure efficiency may be different from a "mash tun" brewing process.

1. [Conversion] Efficiency is most influenced by the quality of the crush. If you don't own the mill, don't expect high efficiency nor should you expect consistent efficiency.

2. Sparging will increase [lauter] efficiency but not by a huge amount. [1 really good dunk sparge gains ~8% lauter efficiency compared to full volume mash] If the crush is bad, sparging will not overcome the deficiency [in conversion].

3. If the crush is poor, a longer mash may be needed to get closer to complete conversion [>95%].

4. Any wort left in the boil kettle reduces [brewhouse] efficiency. Trying to leave the trub behind when you transfer also leaves behind wort.

5. [As long as it's consistent,] Efficiency isn't very critical in home brewing as you can make up poor efficiency by adding only a small amount of extra base malt.

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