Specific Gravity Conversion...Can I Get A Good Reading?

Hi guys. First post!

Friends and I bought a kit, and launched our brewing adventure, the other day. So far, everything is going pretty well. I've got a roiling fermentation going, and I am confident that we kept things clean throughout.

We did, however, screw up our Original Specific Gravity reading with the hydrometer, and I'm wondering if I can convert my reading to an accurate one. Here's what happened:

Instead of taking the sample after we transferred the wort to the 3 gallons of water in carboy (extract brewing), we took the sample directly from the concentrated wort. Yeah, I know...what were we thinking? Anyway, our reading at about 80 degrees was 1.140.

We then strained our wort into the carboy, and topped up to about 5.25 gallons or so (added a little more water, thinking that our reading was WAY too high, hoping to drop our SG a notch or two).

The additional water over 5 gallons is probably not a deal breaker, but it would be awesome to know approximately what my reading would have been before fermentation started. Is it possible to extrapolate what the SG would have been?

We boiled 1.5 gallons in the kettle, along with the various ingredients, for about 60 minutes. 2 lbs of malt powder and 1 can of malt extract would be the main volume additions.

Is there a formula that would get me back to where I started?

FYI, you can see pics here, if that helps.

It was an extract brew so you should be fairly close to whatever the recipe said your SG should be. The additional water you added will have a small effect but if it were me I'd just assume you were close to the recipe SG and go from there.

I use a tool called "winecal" for diluting my wine musts, so I'll give it a stab.

First, at 80 degrees, you need to correct for temperature. My hydrometer is calibrated for 60 degrees (yours may be, or it might be calibrated for 69 degrees). So, the corrected reading is 1.143 with 2 gallons.

So, if you add 3.25 gallons of water (SG 1.000) to 2 gallons of 1.143 wort, you'd get an estimated OG of 1.054.

Another way to do it is to guestimate the fermentables. In a 3.3 pound of extract, you'd get approximately 1.023 in a 5.25 gallon batch. If you added two pounds of dry extract, that would bring you to only 1.039.

So, something is still not adding up. If you only used 2 pounds of dry extract and 3.3 pounds of extract, I'd go with the OG of 1.039 and consider the first hydrometer reading wrong. Maybe it was more than 80 degrees?

Thanks, Yooper. That's exactly what I needed. It's a ballpark, at this point, anyway, but I really just hoped that we were in the range we were supposed to be.

I was basically stuck with having to use the recipe's intended SG for my starting point. The recipe, as it was written was in the low 1.04's, as I recall, though we made some modifications.

We added half pound of steeped crystal malt, and some additional hops, so that might have resulted in a slightly higher SG estimate than the recipe called for in it's pure form, had we taken a solid reading. Going with around 1.039 or so isn't unreasonable.

Hyrdometer calibrated to 60, and we were right at 80 degrees. Obviously there's a +/- factor with our instruments, though. First time we'd used any of them, so user error could have been a factor in other areas of our process.

NM see above

ronzonie7 said:

Hyrdometer calibrated to 60, and we were right at 80 degrees. Obviously there's a +/- factor with our instruments, though. First time we'd used any of them, so user error could have been a factor in other areas of our process.

Click to expand...

LOL---- I read your blog. Um, I would blame the alcohol consumption as the majority of the "user error"!

Steeping crystal grains gives great color and flavor to a beer, but not much if anything in the way of fermentable sugars. So, it's really a negligible addition for adding to the SG. Now, it contributes greatly to the flavor, so it's definitely a great addition!

Anything under about 6 pounds of extract is going to be a lower alcohol beer. I use Beersmith (free trial and download) to figure recipes and the amount of hops, etc. You could play with that, and see how much water/malt/hops to add in these recipes. In your recipe, you're looking at a finished ABV of 3.5-3.75%.

You've got alot of hops for a lower gravity beer. That one ounce of chinook at 5 minutes might take a while to mellow out, but I like chinook. I think you guys are definitely hopheads!

Guilty as charged on the hop head front...and also guilty (though all faculties were not impaired) on the reason behind the hydrometer malfunction...

We have been considering a free trial for Beersmith, and I'm glad to hear some positive things about it being helpful. We have an idea for a pumpkin porter, but we want to make it as a half batch (we also have a smaller carboy for smaller batches). I believe Beersmith will tailor a recipe to the volume we want to brew.

Yes, Beersmith is amazing. Definitely download the trial and use it to calculate your recipe. you can create a profile for your exact setup and it will give you boil volumes and the like specifically for that profile.

good luck and good brewing.

yes it will. beersmith is pretty amazing

Simple.


Take your gravity points by volume (if your OG was 1.140, then your gravity points by volume were .140) and multiply that by your concentrated volume to get your gravity points.

Then divide that by final volume (5.25) and add one.

So if your original reading was at 2 gallons, then your gravity points are .280. Divide that by 5.25 and you get .053, meaning at 5.25 gallons, your OG is 1.053. Very simple and very accurate, if your volumes were accurately measured.

But don't worry. Original Gravity is always almost identical to the expected OG with extract batches. So just go off of whatever your kit or beersmith or promash or whatever said.

It's All-grain that can lend you all sorts of different OGs depending on your efficiency.

Dougan said:

Simple.


Take your gravity points by volume (if your OG was 1.140, then your gravity points by volume were .140) and multiply that by your concentrated volume to get your gravity points.

Then divide that by final volume (5.25) and add one.

So if your original reading was at 2 gallons, then your gravity points are .280. Divide that by 5.25 and you get .053, meaning at 5.25 gallons, your OG is 1.053. Very simple and very accurate, if your volumes were accurately measured.

But don't worry. Original Gravity is always almost identical to the expected OG with extract batches. So just go off of whatever your kit or beersmith or promash or whatever said.

It's All-grain that can lend you all sorts of different OGs depending on your efficiency.

Click to expand...

And here I was, thinking chemistry was a waste of time...If they'd have told me beer was chemistry back in college, I'd be a Chemical Engineer (or have blown myself up trying to ferment something caustic).

I hate chemistry. I got mostly A's in high school, and a D in Chemistry.

But this is algebra, which I am very good at.