Noob Question on Original Gravity

[doubled0508]

Hello homebrew world!

When measuring my O.G for my all grain black IPA, I first measured while fly sparging into my boiling pot at 1.075. I was pleased with this (it was my goal) and decided to sparge the rest.

After sparging all 5gal, I measured again and my wort was at 1.050.

Is my actual O.G. 1.050? Does this prove I mash'd incorrectly?

Thanks for your help!
-Dan

 

[Chefflahertycec]

no. This sounds like a pre boil gravity which will change as you reduce the wort by boiling. I usually gain about 5 - 10 points (1.050 up to 1.060) through an hour of boil depending on gravity. In short, your OG is the gravity of finished, cooled wort before pitching yeast and fermentation.

 

[Qhrumphf]

What was your batch volume and preboil volume? Smaller batch with preboil of 5 gallons? Or 5 gallon batch with a higher preboil? What was the actual gravity and volume after the boil?

Gravity will be low after the sparge, and then concentrate down as water evaporates off during the boil. If the first reading was very early on (ie first runnings) then 1.075 is probably about right depending on the water to grain ratio. The first runnings of the mash will be the highest, and progressively go down the more you sparge (to be concentrated back down in the boil. For example, with my batch today, my first runnings were neighborhood 1.080 or so (of which there were a few gallons), my pre-boil gravity was 1.057 at 7 gallons, and my final batch gravity was 1.075 at 5.3-5.4 gallons.

 

[doubled0508]

Thanks for the quick response. I understand now.

Pre-boil I was in the ball park of 1.050. I failed to take an actual reading of my O.G. before pitching yeast. I am guessing it is in the ball park of 1.065-1.075. What I did not realize (first time brewing) was the amount of evaporation of my wort. Out of a 6gal boil pot I probably ended up at 4.5 gallons. At this point I added .5gal of water before pitching yeast.

Hope the added water was the right thing to do?

 

[Qhrumphf]

With extract brewing, yes, that would be correct. With all-grain and the potential variation in mash efficiency, the goal is to hit gravity, not volume (where with extract brewing the sugar content is more or less known so the right gravity and the right volume should be the same place). What you did won't hurt, and if your mash efficiency was where it was supposed to be, then you'll be at the right gravity. If I have more boiloff then expected and end up over gravity, I'll top off with water. But if the gravity is right and the volume is not, I'll leave it right where it is.

If you were at exactly 1.050 at exactly 6 gallons, you were at 1.067 at 4.5 gallons, and 1.060 at 5 gallons. However, there's other variables (temp corrections, stratification of runnings, volume and gravity errors, etc). So without an actual measured OG, who knows where you actually were.

 

[doubled0508]

I see I see. None the less my first batch ever won't be perfect as expected. It am expecting it to still turn out as a solid IPA.

The next batch I am going to try out is a Imperial Stout I threw together https://www.brewtoad.com/recipes/giantsbane-imperial-stout

I will most definitely purchase a 8gal brewing pot for this batch to calculate for evaporation.

Thank your for your help,
-Dan