# Efficiency Calculations Are Off

Brewed an Irish Blonde yesterday. Efficiency reading came in at 107%. Not possible, I know.

Here’s how I’ve been measuring…

After mash and sparge are complete and all the wort has been extracted, pull a sample after thoroughly mixing.

The pre-boil volume in the boil kettle was 11.25 gallons (for a 10 gal batch).

So I took a gravity reading of the sample, and after adjusting for temperature, the gravity came in at 1.077.

The OG of the beer is only supposed to be 1.063!

After running the numbers through the Brewers Friend efficiency calc, it gave me 107%.

I checked my hydrometer in 60 degree water to verify that it was accurate…it is.

I let the sample cool down to room temp and took another measurement…still higher than the OG of the beer should have been.

After the boil and chill, the OG came in exactly where it should be at 1.063.

Either my wort isn’t fully mixed (not likely) or the Brewers Friend calculator is off, or I’m doing the whole process wrong.

Thoughts?

Sounds like you got a biased sample of wort. I have had that happen many times before but with a refractometer.

So the SG DECREASED after boiling?
You said it brother-impossible.
Since your 1.063 prediction was exactly what you experienced, there must have been a wort stratification in the original check.
Leads to a point- As long as my OG is within a couple points of my prediction, I don’t care what my efficiency is. Of course, I continue to take readings at every stage…
:cheers:

[quote=“stompwampa”]
Either my wort isn’t fully mixed…[/quote]
I don’t know why this seems more difficult than it should be, but it is a common problem. I bring my wort to a boil, then take a sample to calculate OG and efficiency. Historically, that gets it mixed well enough for me to get a reliable measurement.

The reason I suspect that it wasn’t due to the wort mixture is because I’ve always been extra careful to mix it up like a mad man.

Not saying it isn’t possible…just seems unlikely for as furious as it all gets mixed before pulling a sample.

But yea…I only really care about the OG reading going into the fermenter…I just like doing efficiency calculations because it’s interesting.

Probably your hydrometer was floating on some crap in you sample. I always bounce and spin mine a few times to make sure.

Actually, that makes perfect sense. There was tons of hot break in the wort sample…and I don’t recall doing the bounce spin thing.

[quote=“stompwampa”]
Not saying it isn’t possible…just seems unlikely for as furious as it all gets mixed before pulling a sample.

But yea…I only really care about the OG reading going into the fermenter…I just like doing efficiency calculations because it’s interesting.[/quote]
I hear you, it just seems to happen to a lot of brewers who feel they have mixed well. I think wort is just difficult to mix, for some reason.

You can calculate efficiency from any step in the kettle, as long as you know the volume, but I find it easiest to get a mixed sample at the start of the boil and I usually have little to do but watch the kettle boil at that point. But it doesn’t matter if you take the reading at the start or end of boil, if you have the current volume in the kettle. A dip stick is useful for that.

There are a lot of good reasons to regularly get a gravity reading before the boil. For example, if you miss your target you can boil longer before you add hops to get the gravity closer to what you wanted or cut back on the bittering to compensate. It’s also useful to monitor efficiency, since a sudden change can be a sign of another problem, like a slipped mill adjustment, a tun design issue that isn’t allowing it to drain completely, a thermometer that needs calibration, or a change in your water that is throwing off the pH.

If you know your boil gravity is not where you want it you can boil the wort down till you reach it. Then do your additions. If you wait till you get your OG after boil and its low sure you can boil more but that would mess up all your addition times. I guess that was already mentioned.

This saved a few batches for me a lot before I got the kinks worked out of my system. If you get the gravity after you add the bittering hops, you can boil longer to concentrate the wort and not change the beer very much. If you get the gravity before you add the hops, you have an opportunity to rethink the beer and change the amount of bittering to suit the wort that you made. If you come in with a low gravity, for example, you might change an IPA to a Pale Ale, a Pale Ale to a Bitter, or maybe a Porter to a Brown and end up with a decent beer.

This saved a few batches for me a lot before I got the kinks worked out of my system. If you get the gravity after you add the bittering hops, you can boil longer to concentrate the wort and not change the beer very much. If you get the gravity before you add the hops, you have an opportunity to rethink the beer and change the amount of bittering to suit the wort that you made. If you come in with a low gravity, for example, you might change an IPA to a Pale Ale, a Pale Ale to a Bitter, or maybe a Porter to a Brown and end up with a decent beer.[/quote]
My astute wife said " oh I get it, whenever you screw up you call it a pale ale or a brown ale depending on the color" Nothing gets by her.