OG Consistently Low

[Davida]

I have been home brewing for a couple years now and have turned out some pretty awesome brews (thanks HBT!).
I am an extract brewer and always do partial boils (2 - 2.5 Gal).
Almost every brew the OG is consistently lower than what is called for in the recipe. Recently, I brewed an amber ale. Target OG was 1056. Mine came in at 1044. Typical for what I am seeing on a regular basis.
Any hints?

 

[Jayhem]

Since you do partial boils the top off water you used to get back to 5.0 gallons is very difficult to get to mix evenly with the high sugar wort. Vigorous stirring is required to bring the final wort to a uniform dilution before measuring gravity.

Also your hydrometer could be off. Have you tried it in distilled water to make sure it reads 1.000?

 

[Davida]

Thanks for the reply.
I have checked the calibration of the hydrometer. It's right on.
When I combine the wort with the water I use a whip and stir it vigorously.
I also pass all brews through a settling tank to reduce the trub in the primary.
When racking to the fermenter I once again stir vigorously with a whip to aerate the wort.

 

[duboman]

Thanks for the reply.
I have checked the calibration of the hydrometer. It's right on.
When I combine the wort with the water I use a whip and stir it vigorously.
I also pass all brews through a settling tank to reduce the trub in the primary.
When racking to the fermenter I once again stir vigorously with a whip to aerate the wort.

Your hydrometer should read 1.000 in distilled water at its own calibrated temperature, most are 60F but some are different, it should say on the label strip. Be sure to temperature correct your readings as well.

 

[stratslinger]

OK, are your brews kits, or are they assembled recipes, or some combination of the two? If they're recipes, how are you measuring the amounts of extract you're using? Is it possible you have a faulty scale, and you're using less extract than you think you're using?

 

[Davida]

I work from recipes, most right here at HBT. I do tweak them a bit here and there. But nothing that should affect the gravity so radically.
I didn't think about calibration of the scale. I will check that next.
We can change this topic to varying OG.
I brewed a stout yesterday that had a target OG of 1058.
I got 1074! The sample did have some solids (trub), which could have affected the gravity a bit...

 

[dfc]

I always mixed my partial boil recipes thoroughly by running everything through my bottling bucket into my fermenter (check link in sig). I've never had any faulty readings doing things this way and I've made over 30 batches this way and checked OG every single time.

Also, how are you varying recipes?

 

[Jayhem]

I work from recipes, most right here at HBT. I do tweak them a bit here and there. But nothing that should affect the gravity so radically.
I didn't think about calibration of the scale. I will check that next.
We can change this topic to varying OG.
I brewed a stout yesterday that had a target OG of 1058.
I got 1074! The sample did have some solids (trub), which could have affected the gravity a bit...

Just FYI, trub floating around in the wort won't effect the gravity much since if it's floating around it is the same density as the wort, therefor no effect on your hydrometer. I thought the same thing awhile back.

 

[stratslinger]

I work from recipes, most right here at HBT. I do tweak them a bit here and there. But nothing that should affect the gravity so radically.

OK, this line kind of has me intrigued...

You're working from recipes, yet you're tweaking them but you believe those tweaks shouldn't be affecting the gravity so radically. Which begs the question: where are you getting your expected OG from? If you're using your tweaked recipe and comparing its OG to the projected OG of the untweaked recipe, regardless of how minor you believe your tweaks to be, that can be one source of variance.

If, on the other hand, you're plugging your tweaked recipe into a software tool like Beersmith or Brewtarget or something like that, then that should give you a more accurate idea of what you should expect for an OG. Not sure which of these scenarios apply to you.

Another thing that I should have thought of is innacuracy - either on your part or on the part of whoever wrote the original recipes you're working from - in volume measurement! If, for instance, a recipe calls for enough extract to make 5 gallons of wort with a given OG, but your measurements are a bit off and you're actually making 4.75 gallons, your OG will be a bit high. Or if you make 5.25 gallons, your OG will be a bit low. Keep a close eye on volumes!

 

[duboman]

OK, this line kind of has me intrigued...

You're working from recipes, yet you're tweaking them but you believe those tweaks shouldn't be affecting the gravity so radically. Which begs the question: where are you getting your expected OG from? If you're using your tweaked recipe and comparing its OG to the projected OG of the untweaked recipe, regardless of how minor you believe your tweaks to be, that can be one source of variance.

If, on the other hand, you're plugging your tweaked recipe into a software tool like Beersmith or Brewtarget or something like that, then that should give you a more accurate idea of what you should expect for an OG. Not sure which of these scenarios apply to you.

Another thing that I should have thought of is innacuracy - either on your part or on the part of whoever wrote the original recipes you're working from - in volume measurement! If, for instance, a recipe calls for enough extract to make 5 gallons of wort with a given OG, but your measurements are a bit off and you're actually making 4.75 gallons, your OG will be a bit high. Or if you make 5.25 gallons, your OG will be a bit low. Keep a close eye on volumes!

This!!! While you might not think you are drastically doing anything are actually taking the time to figure out exactly what the results of your tweaking are????

Just adding a few ounces of something or grams or whatever can have a larger effect on your final product than you think. Honestly, this would've been a nice piece of info to have been included in the original post....

 

[Davida]

I should have said "sometimes" tweak the recipes. The first time I try them, I do follow them to the letter, and still notice variances in OG.
The tweaks are nothing radical like adding pounds of malt. I didn't think adding 4 oz of grain to the grain bill would have an adverse affect. A few thousandths on the hydrometer maybe, but hundredths? Volume could be a key factor.
I think it's time to invest in some brewing software to support my growing addiction!