Help checking my numbers

[akinsgre]

I just made a batch and measured Wort Gravity so I can could calculate my efficiency. From my calculation, it looks like 40% - 56% (Ugh) Would you all look at my numbers to see if you can spot anything I did wrong?

5 gallon batch started with 7 gallons of water (I'm not sure which to use)

1 lb Crystal 40 - Max PPG 34 - points 4.8
1 lb Crystal 120 - Max PPG 33 - points - 4.7
1 lb Victory - Max PPG 35 - points 5
1 lb Caramunich - Max PPG 34 - points 4.8
11 lb Mariss Otter - Max PPG 38 - points 59.71

From that I calculated total points as 110 - 79 depending on n gallons of water

Gravity was 1045

(Using information from Palmer's book to do this)

 

[akinsgre]

Sorry I should have mentioned that I mashed for 60 minutes my temp started around 160 and was at 156 by the end of the mash. Sparged with 170

 

[meatwad]

So, I don't want a calculator online web tool or app.
Can you guys point me in the direction of the actual formula, that I can work through and get my eff. With PPG sheet and everything?
Can't seem to find it.

I have one and I calculated 54% efficiency, which could very well be accurate. But I'd like to double check my work.

Cheers!
Meatwad

 

[Calder]

1 lb Crystal 40 - Max PPG 34
1 lb Crystal 120 - Max PPG 33
1 lb Victory - Max PPG 35
1 lb Caramunich - Max PPG 34
11 lb Mariss Otter - Max PPG 38

Total points available = weight of grains x max PPG.

In this case = 1x34 + 1x33 + 1x35 + 1x34 + 11x38 = 554

(NOTE: 38 points for Maris Otter seems high, I would have guessed 36).

Next: How many points did you get? You said the gravity was 1.045. You didn't say if it was for 5 gallons or 7 gallons, and you didn't say if you corrected for temperature (it can make a big difference).

Let us assume you did correct for temperature and the gravity was for 7 gallons (measured pre-boil). Then you would have extracted 7x45 = 315 points.

To calculate your efficiency you divide the points extracted by the total available points and multiply by 100.

In this case = (315*100)/554 = 57%

 

[akinsgre]

Thanks Calder.

The wort size was 7 gallons (the batch size for the brew, after boil, was 5 gal) I wasn't sure which number to use. I guess 7 gallons makes sense since we're measuring the density of the wort before it's boiled.

I didn't correct for temp. The John Palmer book didn't mention that. Do you have any links explaining that?

You're numbers are close to mine. I appreciate you checking that for me.

Now to figure out how to get that number higher.

 

[Calder]

I didn't correct for temp. The John Palmer book didn't mention that. Do you have any links explaining that?

Google 'Hydrometer Temperature Correction' and you will get lots of sources.

Palmer was the second one that came up for me (Appendix A).

The measuring temperature can make a lot of difference. Hydrometers are calibrated for 60 F. At any other temperature the reading is wrong and should be corrected. The temperature that is important is the wort/beer temperature.

For example: If the wort was 70 F you would add .001 to the reading.

At 75 F add .002.
At 95 F add .005
At 118 F add .010.

As you can see, if the wort you were measuring was straight from the kettle, your reading could be way off.

In your case, for you to have gotten 75% efficiency, your measurement would have had to have been at 145 F. This would give you a correction of .014 giving a corrected gravity of 1.059.

 

[akinsgre]

Thanks again.

I didn't correct and did measure straight from the mash tun. So, I was probably at at least 130F Giving me much better numbers than I originally thought.

I'll the appendix and pay much closer attention during my next bash.