LME Calculations Help?

[The Hansa]

Yesterday, I brewed a beer that was meant for all grain with a majority of LME... The predicted ABV was 8% but I hit over the mark with an OG of 1.110 which suggests that beer will hit around 12%... In retrospect I now know that this was due to the LME, but the question I have is how do I calculate how much LME I should use if I find myself in a situation like this again or is it the malt
Grain Bill For 5 Gallons:
5lb of Vienna Malt (Step Mash)
7lb Bavarian Wheat LME
5lb Munich LME
0.19oz Molasses

 

[BrewnWKopperKat]

What was the initial recipe's target OG?

 

[The Hansa]

What was the initial recipe's target OG?

1.071

 

[The Hansa]

I am going to take another reading soon... I will admit that I measured the wort when it was too hot but now it has cooled below 100 and I should get a better reading... plus I haven’t pitched any yeast

 

[BrewnWKopperKat]

I hit over the mark with an OG of 1.110

• 10 lbs base malt at 75% efficiency is roughly SG 54.
• 7 lb LME (36 PPG) would add roughly SG 50.
• estimated OG: 104.

1.071

For an OG of 71, the LME would need to contribute SG 17 (71 - 54) or roughly 2.4 lbs of LME.