Low starting gravities on IPA's - too much water?

[andruss15]

Good afternoon folks,

This past weekend I brewed a White IPA using extract and found that the starting gravity was much lower than anticipated. The target was 1.067 and the actual came in at 1.052. I used extra top off water to bring the total volume to 5.25 gallons and stirred it very well before taking the reading. Is it possible that the sample I took was incorrect? I also used 2.5 gallons in the brew kettle although I realized afterwards that the recipe called for 2.0 gallons during the boil. (I actually made the same mistake with a previous IPA which ALSO came out to have a low starting gravity.) Would the additional water during the boil cause a low starting gravity?

The brew is currently vigorously fermenting away. Any thoughts would be helpful!

 

[Gameface]

I'm assuming this is from an extract kit?

Your total water volume post boil is what will determine your starting gravity based on the amount of extract used. With extract, if you use the right amount of extract and end up with the right amount of volume as per the recipe then you will get the advertised starting gravity. No two ways about it. If you have more volume than what the recipe calls for then your gravity will definitely be lower than what the recipe said it would be. Or if you spilled some of the extract on the floor. But with a given amount of extract in a specific volume of water you will get an absolutely predictable starting gravity.

 

[andruss15]

Yes it was from an extract kit. The previous IPA I brewed used the correct total volume of water and still came out with a low gravity - there was no boil over or any spillage but again, I did boil the wort in 2.5 gallons of water instead of the recommended 2.0.

 

[Yooper]

Yes it was from an extract kit. The previous IPA I brewed used the correct total volume of water and still came out with a low gravity - there was no boil over or any spillage but again, I did boil the wort in 2.5 gallons of water instead of the recommended 2.0.

The issue may simply be taking a five gallon batch recipe and diluting it to 5.25 gallons, especially if you don't measure the five gallon volume exactly. Adding more water will make the SG lower.

 

[Gameface]

Yes it was from an extract kit. The previous IPA I brewed used the correct total volume of water and still came out with a low gravity - there was no boil over or any spillage but again, I did boil the wort in 2.5 gallons of water instead of the recommended 2.0.

Boiling in 2G vs 2.5G has nothing to do with the lower gravity. You're topping off with water either way, so it's all about the total volume that goes into the fermenter.

Based on what you've said, my guesses would be that you either are not measuring your total volume correctly or your wort wasn't was well mixed as you thought.

So do I have this part straight, that your first batch was 5G and also had a low SG and your most recent batch was 5.25G for a recipe that called for 5G?

 

[andruss15]

Yes, both recipes called for 5 gallons, both had low SG, and the most recent one was topped off to 5.25 gallons which was measured out.

Thank you for the replies so far

 

[lolcats]

This won't help, but IMO 1.052 is a better SG for a White IPA than 1.067 unless it's a double

 

[Gameface]

Yes, both recipes called for 5 gallons, both had low SG, and the most recent one was topped off to 5.25 gallons which was measured out.

Thank you for the replies so far

How are you determining your total water volume?

 

[andruss15]

How are you determining your total water volume?

I have a regular bucket for the primary fermenter with a 5 gallon marker. As for the additional water there was no math, if that's what you're asking. I just measured out an extra .25 gallons using measuring cups.

lolcats - Thank you for the advice, any help or thoughts are appreciated. The recipe calls for a final gravity of 1.010

 

[Gameface]

There was no math, if that's what you're asking. I just measured out an extra .25 gallons using measuring cups.

lolcats - Thank you for the advice, any help or thoughts are appreciated. The recipe calls for a final gravity of 1.010

So how do you know the total was 5.25 gallons?

 

[andruss15]

After topping off the wort to 5 gallons in my primary fermenter, I measured out 4 cups (0.25 gal) and then added that.

 

[Gameface]

After topping off the wort to 5 gallons in my primary fermenter, I measured out 4 cups (0.25 gal) and then added that.

How do you know there was 5 gallons in your fermenter?

I'm asking because fermenter markings can be off, and sometimes by quite a bit. Also, volume has everything to do with your SG when using extracts, so that's by far the most likely cause of the discrepancy.

My advice would be to verify that your volume markings are accurate and go from there.

 

[andruss15]

I didn't realize they could be off by so much! Thanks for the advice, I'll try that before my next brew to see if that's the issue.

 

[stratslinger]

The way I see it, there are 2 things potentially at play:
1) As has been pointed out, markings on fermenter buckets can be notoriously innacurate. Same rule of thumb goes for any vessel that has volume markings - check them to confirm, and figure out what you need to do to adjust up front. For example, I got a pair of plastic big mouth bubblers this past christmas. They come with volume markings - but each "gallon" marker is between a quarter and a half inch thick. In a vessel the size of one of these fermenters, that can be a swing of almost a quart from the bottom of the marking to the top. Add to that that the bottom of the first marker is about a pint over a measured gallon, and the whole set of markers is WAY off.

2) If you don't mix in your top off water REALLY thoroughly, you're likely to get some stratification of wort before the yeast get to work mixing things up further. This typically means that towards the top of your fermenter gravity readings will tend to be lower than towards the bottom. Mixing really thoroughly will reduce this problem. But, as was already pointed out, for extract, so long as your volume is definitely what the recipe calls for (see 1)), your gravity will come out as advertised.