I brewed a pale ale yesterday and had a SG of 1.050. My beer smith had it 1.060. so I missed it by 10 points. I also collected 3liters (.79gal)[b] more in the fermenter.
My question is how much would the extra 3litres effect my gravity?
Since you were off on volume (more than expected) it threw off your OG because it was more watered down. Your overall gravity or abv will be slightly lower due to the extra volume. You will also have a few extra pints of beer.
That depends on your target/actual volumes. If you were shooting for 5 gallons but ended up with 5.79 gallons @ 1.050, boiling off the extra 0.79 gallon should put you around 1.058.
The formula is “target gravity points * target size / actual size” = “actual gravity”. 60 * 5 gallon / (5 gallon + 3 liter) = 52. You would expect an OG of 1.052, which almost entirely accounts for your discrepancy.
Better to leave some water in the tun than water down the wort. Check your volume after your first run and only sparge with the volume of water needed for your target. You can save the extra wort in the if you have extra wort save it in the freezer for starters,
