[Just saw your post above. Will come to it in a second.)
Congratulations Lee
,
Hope all went well for you.
BrewBagMan wrote: Not to be one who is super caught up in the numbers, however I wouldn't mind, if possible, simply knowing how efficient my brew day was.
Good. It's most important to not get obsessed with numbers.
BrewBagMan wrote: Just wondering if anyone has a super straight forward explanation how on to calculate this?
No. (you'll see why later).
The logic of an efficiency calculation is actually very simple. All you are basically doing is comparing how much 'sugar' you have in your wort compared to the amount they were able to extract in the laboratory.
Here's a simple example...
A Simple Example
Let's say you used 10 pounds of grain in your brew and you knew from the laboratory that your grain had an extract potential of 35.5 ppg. This means that if you are hundred percent efficient, you should score...
10 * 35.5 = 355 gravity points in your brew.
Let's say you at the beginning of your boil, you had 7 gallons of wort (after allowing for shrinkage due to cooling) and that wort had a specific gravity of 1.040. This means you scored 7 * 40 = 280 gravity points. (Gravity points are the numbers to the right of the decimal point in a specific gravity, multiplied by a thousand).
So, 280 / 355 = 78.9 % EIK (Efficiency into Kettle)
At the end of the boil, you might get say 5.6 gallons (after allowing for shrinkage due to cooling) at a specific gravity of 1.050 which also equals 280 gravity points (5.6 * 50).
So your EOB-E (End of Boil Efficiency) is also 78.9%.
(EIK and EOB-E should be close to each other. While you have less wort at the end of the boil, the gravity is higher.)
Let's have a look now at what happens at the pitching stage. Let's say you get 5.0 gallons into your fermentor. (In other words, you lost 0.6 gallons to trub). The specific gravity will not be any different from the end of the boil so now we have 250 gravity points (5 * 50).
So, 250 / 355 = 70.4% EIF (Efficiency into Fermentor)
Normal brewing practices always involve some sort of kettle trub losses so EIF will always be lower than EIK and EOB-E. The discrepancy between them is an indication of your trub losses. EIF does not contain anywhere near the amount of valuable information as EIK or EOB-E
The Reality
The reality of working out the calculation can be horrendously complex because maltsters can list the extract potential of their grains in many different ways. In your grain bill, you may have one malt with a listed extract potential of 76.8% while another malt may have it listed as 35.5 ppg. Another grin may have the extract potential listed as LDK. Another may have it listed as 80% FGDB with 4% MC.
See what I mean?
And what if you are a metric user and...
Furthermore, the extract potential from one batch of grain from the same maltster may vary considerably. Unless you have the spec sheet for that batch of grain, you are already approximating things.
A Simple Way Around This
There are many simple ways to work out efficiency in both metric, imperial and US customary units. I was going to show these but the post will get too confusing.
All these simple methods hinge on using a good "average" extract potential. (For example, the 35.5 ppg is what the BIABacus uses unless you over-ride each individual fermentable)).
What We Can Do
Hopefully the above explains both the simplicity and complexity of efficiency calcs.
There are many ways to answer your question. For example, we could answer it in metric. Or we can show you what fields you need to fill in in the BIABacus to get your answers.
Let's take a break at this stage though so as you can digest the above.
Probably the next step is to look at what raw information you need. I'll write this a bit later on.
Congrats again
PP
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