Lots of yum full-strength beers last night which lead to a bit of ranting in my last post here
. Lots of truth in that rant though. It is very important to use Clear Brewing Terminology. For example, "Brewhouse Efficiency" can mean either kettle efficiency or fermentor efficiency depending on how the brewer has set it up. "Batch Size" in BeerSmith, also depending on the set-up can mean either Volume into Fermentor or Volume of Ambient Wort. Officially, Beersmith's definition relates to fermentor measurements but due to errors in the program, many users set the program up a different way to correct the errors. (A very long story.)
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Any sort of efficiency is about volume and gravity[/center]
I'm going to copy, edit and paste two PM's I wrote last week to a new member trying to explain measurements and efficiency. Here you go...
Here's what you want to do on your brew day....
1. Take one gravity and volume measurement at the start of the boil. When the wort starts boiling, turn the flame off, measure the volume as best as you can and grab a coffee cup full of wort from the kettle. Cover that with plastic wrap and put it in a water bath for it to cool. Once it has cooled, pour it into a hydrometer jar and take a gravity reading. Pour the wort back into the boil.
The above is a preliminary check on your "kettle efficiency" which is nothing you need to worry about [EDIT: More later.]
2. Do the same as the above at the end of the boil. This is your second check of your kettle efficiency. Theoretically it should be the same as the above but it hardly ever is due to the difficulty in taking measurements at near boiling temps. It is important to do these checks though as they can act as confirmations of a problem.
3.Once you have cooled your wort and transferred it to the fermentor, aerate it well and, using a sterilised mug, grab another sample of well-mixed wort. Take its gravity in a sanitised hydrometer jar and then that sample can also go back in the fermentor if you are pitching straight away.
The gravity readings taken in steps 2 and 3 should be the same or very close. If not, get another sample and re-check your reading.
.....
Most brewers will only take one gravity reading at the end of the brew but one reading is very unreliable. Worse still is taking early readings and adjusting the brew at the boil's beginning.
Doing the above, you can be confident in your readings and the following will be the most likely result...
You'll most likely find that you have less wort than you were expecting but at higher gravity. You can then play with Section N of The BIABacus in the 'Extra Water Added to Fermentor' field until your Expected Original Gravity in Section P equals what you want.
If your tap water tastes fine and you are pitching straight away, just use that otherwise boil it and cool it first.
The reason we want to end up with less wort at higher gravity is because it is much better to dilute a strong wort than to add DME to a weak wort.
You can never predict evaporation etc on a brew day so you always really want to be aiming at this stronger wort scenario to keep you on the safe side.
[End of first PM]
Just think of Efficiency as a Sugar Score
On the efficiency side, just think of it as a "sugar score". For example...
At the beginning of the boil you might have 30 litres of wort at 1.035 gravity (Note that 30 x 35* = 1050 "sugar score").
At the end of the boil, you might have 21.5 litres at 1.049 gravity (Note that 21.5 x 49* = 1053.5 "sugar score")
[*The 35 and 49 above come by just getting rid of the 1.0 part of our gravity readings. i.e. 1.035 becomes 35.]
Notice how 1050 and 1053.5 are almost identical? (On a real brew you wouldn't get it that close for reasons mentioned previously.) But what this shows you, is that your "sugar score" does not change during the boil.
Another way of looking at it is like this. If you poured a bag of sugar into a saucepan the more you boiled it, the sweeter the liquid would taste. No sugar evaporates off.
This is why the estimated "kettle efficiencies" (EIB and EAW) in the pic below are identical. Also note how the actual kettle efficiencies are not identical but are fairly close to each other? This tells the brewer that he is well within the ball-park and is going well.
Efficiency.jpg
Why is Efficiency into Fermentor (EIF) lower than the "Kettle Efficiencies?
The reason for that is our "sugar score" is actually lower after we transer from kettle to fermentor because we leave real sugar behind in the kettle trub etc,. For example...
We had a sugar score of 1053.5 (21.5 x 49)
When we transfer to the fermentor, we might leave 3 litres behind in the kettle but our specific gravity doesn't change at all in that transfer so we end up with...
18.5 L at 1.049 which is 18.5 x 49 which is a sugar score of 906.5 which is a lot less than our kettle sugar score.
How does Sugar Score Relate to Efficiency?
An efficiency measurement basically turns your sugar score into a percentage which, on top of a lack of clear definitions on other sites and in other software, can really confuse new brewers. (Hardly any brewers, even experienced ones, understand efficiency correctly and from all angles. Only the smallest percentage are aware of just how many problems this causes.) The only things that you need to understand though are...
1. Your kettle efficiencies (EIB and EAW) should hopefully end up being within say 5% of each other and always be higher than or equal to the BIABacus estimates.
2. Kettle efficiencies will always be higher than fermentor efficiency because we do lose sugar in our transfer from the kettle.
Let me know if that helps at all...
[End of second PM]
To finsh off...
Snaylor, MS mentioned above, supplying your BIABAcus files. If you still have them or any, then post them as when we do have the files, it only takes a few seconds to identify a consistent brewing error. If you don't have any, make sure you do the measurements described in the beginning of this post and record them in The BIABacus. This identifying of any major brewing errors is another thing that The BIABacus does extremely well but that other programs "muddy".
PP
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