Gravity issues

[mzukovsky]

Today my pals and I brewed an IPA over 120 minutes. We started with 9 gallons and put 5.5 gallons in the fermenter after 6 ounces of hop additions during the boil. Our pre-boil Gravity was 1.067 and our post-boil was 1.076. The post-boil Gravity was far from the 1.100 that was calculated. Does anyone have input on what the problem may be or if we even have a problem?

 

[beskone]

Recipe, process?

You haven't given near enough info to even start to figure out what happened.

 

[kh54s10]

Did you account for temperature for your Gravity readings? If you had 9 gallons or 1.067 and boiled down to 5.5 gallons you definitely should have the 1.100.

So it is either mistaken gravity reading(s) or your volumes were different.

 

[mzukovsky]

What I was getting at is utilizing the boil off calculator on Beersmith, after boiling off 3 gallons the Gravity should have changed as noted in the original post. But, if it helps, the original recipe was 16 pounds of 2 row and half a pound of Fawcett Amber malt. The pre-boil Gravity was adjusted for temp.

 

[mzukovsky]

The post boil Gravity was measured twice. It was after we transferred to a carboy, but, before adding yeast. Everything in the carboy had clearly settled, would that make a difference?

 

[doug293cz]

Is the 9 gal the starting water volume or the pre-boil kettle volume? In addition to your grain bill, we need the following:

• Strike water volume
• Fly sparge or batch sparge, and if batch then number of sparges
• Sparge water volume (for each sparge)
• Pre-boil kettle volume and the temperature at which it was measured.
• Volume losses going from kettle to fermenter (or post-boil kettle volume at RT)

Brew on

 

[oujens]

I don't know if I'll be help but thought I would throw some things out for confirmation. How do you measure pre-boil volumes? Do you have gallon markings? Are you able to confirm you boil off 3 gallons in 2 hours, or 1.5 gallons in one hour? Before your pre-boil gravity reading, do you stir it to make sure the wort is thoroughly mixed?

 

[CGish]

What I was getting at is utilizing the boil off calculator on Beersmith, after boiling off 3 gallons the Gravity should have changed as noted in the original post. But, if it helps, the original recipe was 16 pounds of 2 row and half a pound of Fawcett Amber malt. The pre-boil Gravity was adjusted for temp.

For what it is worth, 16 lbs of 2 row and a half pound of amber malt in BeerSmith gives me an O.G. of 1.076. The pre-boil gravity is 1.047 at 9 gallons. This assumes an efficiency of 70%.

To get to 1.100 O.G., you would need 21 lbs of 2 row and 0.75 lbs of amber malt. This would give you 1.062 pre-boil gravity at 9 gallons and 1.100 O.G. at 5.5 gallons.

It sounds like your pre-boil gravity readings was off.

Edit: Or, like doug293cz and ougens point out, your volume readings are off.

 

[m1k3]

Also, to add to @CGish

Efficiency for most folks goes down when using more grain and under sparging.
So, if you get 70% with 16#.... you may not expect 70% with 21#

For me 1.100 OG is hard to hit.... I'd plan for 50% and add water if needed.

 

[m1k3]

https://www.homebrewtalk.com/showthread.php?t=178063