Actual Efficiency

Aloha,
    What formula is used to calculate the 'actual efficiency' column in the recipe view?  I'm getting some strange results for my recipes and for one get no result, the column contains only a dash (-).

The calculation is basically the reverse of the "original gravity" calculation - rather that estimating the original gravity, it works backwords from the measured original gravity to determine the actual efficiency.

Note that you must enter the "Measured OG" to get an accurate "Actual Efficiency".  Also you need to make sure the recipe is an "All Grain" or "Partial Mash" recipe - it can't be an extract recipe.

Finally - the calculation uses your "batch volume" parameter - so if you finished with a batch of significantly different size the calculation can be thrown off proportionally.

Cheers!
Brad

In the recipe that I'm not getting a reading for - I've entered the measured OG, it's set as a partial mash, I'm not sure why I'm not getting an efficiency number.

When you say the calc is based on the batch volume parameter, are you referring to the batch size field in the recipe or the final volume field in my equipment profile?  Or is it when these two numbers are different that the calc can be thrown off?  For example: My equipment profile has a final volume of 5.25 gal.  I have a recipe that the batch size is set to 5 gal.  With my brewhouse efficiency set as 70% I'm getting an estimated OG of 1.057.  My measured OG is 1.062.  My reported actual efficiency for this recipe is 155%.  I'm not sure how I'm getting an actual efficiency of over 100%.

By the way, thanks for the quick responses to this and all of the other questions/suggestions I've been posting the last few days.  The program is great, I've just been running into a few questions as a new user...

Pat,
 Could you email the recipe to me?  Its not obvious to me what might be going on here, but I can probably sort it out quickly if you email it to me.

Thanks!
Brad

......the calculation uses your "batch volume" parameter - so if you finished with a batch of significantly different size the calculation can be thrown off proportionally.

Cheers!
Brad

Click to expand...

Brad,

My low efficiency was a concern to me until it was pointed out that Beersmith uses the Batch Volume field to calculate the Actual Efficiency but it does not take into account the "Loss to Boil Trub and Chiller". Therefore, Beersmith is telling me that I have collected 23L of 1.0XX gravity wort, when in fact I have collected 27L due to 4L of kettle losses. The result of using just 23L in the calculation is a much lower Actual Efficiency shown on the Recipe View.

To get around this anomoly, I set "Loss to Boil Trub and Chiller" at zero and increase the Batch Volume by 4L.

Beersmith then recognises that 27L of 1.0XX gravity wort has been collected and calculates the efficiency accurately.

Personally, I would prefer for the program to recognise that 23L is in the fermenter plus 4L left in the kettle to arrive at the 27L post boil volume but the result is the same.

Perhaps this can be addressed in a future update?

Regards
Steve

Steve,
 A reasonable request - but the reason I went the way I did was because I wanted to match the "brewhouse efficiency" which is basically your gross system efficiency with your "actual efficiency".

 I therefore made the "actual" efficiency simply the reverse calculation of the "brewhouse" estimate.  This gives you constant feedback as to whether your brewhouse efficiency matches your actual.

 What I've thought of doing is to create a separate calculation or tool that allows you to input the final volume (and perhaps losses as well).  This would let you calculate efficiencies with higher precision even though it would not precisely mirror your brewhouse estimate.

BTW - the problem Pat was having was related.  He was partial mashing a very small amount of grain, and when the overall OG did not match the predicted (probably due to some volume variation) it would throw the calculation off wildly.  Since the extract is counted as totally soluable, the grains were not sufficient to account for the variation by themselves.  A measured final volume (OK I need to add this feature) would have given a much more accurate number.

Cheers!
Brad

Brad:  

I am having the same problem as Pat (5/14/04).

You have my recipes on the October/04 list.

The beers were GREAT, but the AE was really high.  When I tried to correct them they doubled +/-!

What might I be doing incorrectly...still learning...love the program!  

Yes,
 The problem with calculating efficiency for a partial mash is that the contribution of the grains is often only a small part of the overall starting gravity.  Therefore even small variations in the starting gravity (due to measurement, volumes lower or higher than the target, variation in malt extracts used, etc) can really throw the whole calculation off and make it difficult to determine your partial mash efficiency.

 For example, if you are off only by a few points on a batch where you might be mashing only 4-5lbs of grain and adding 6 lbs of extract, the efficiency calculation can be heavily skewed.

 In the future what I probably need to add is a "Mash efficiency" calculator tailored to partial mash brewers so you can calculate the efficiency of only the grains mashed by taking a reading after sparging, but before adding other malts.  This would give partial mash brewers an accurate efficiency number (at least for the mash and sparge).

I just added this to my "to do" list for version 1.4.  It is not that hard to add actually.

Cheers!
Brad