Question on Gravity

Dennis1979 · 10-20-2008, 03:59 PM

I have a question regarding specific gravity. I have done 2 batches now. Both recipes stated an expected OG. In both cases my OG came out about .010 higher than what the recipe said it would be. I would think that using the exact ingredients and the stated boil times it would come out closer to what the recipe said.

On the first batch the FG came out pretty close to what the recipe said it would be but using the higher OG and running it through the calculation gives me an ABV of approximately 7% which is kind of high (1.064 – 1.011 / .00738 = 7.18%).

On my second batch (cooked up yesterday) the recipe said OG would be 1.047 and my OG came out 1.060. So assuming a FG in the proper range, I’m looking at high alcohol content again.

Any thoughts? Is there something I should be doing different?

Dennis

**BigKahuna** · 10-20-2008, 04:06 PM

Quote:

Originally Posted by Dennis1979

the calculation gives me an ABV of approximately 7% which is kind of high (1.064 – 1.011 / .00738 = 7.18%).

Try This:
1.064 - 1.011 = 0.053
0.053 x 131 = 6.95%

Still very high...but it's a bit easier of a calculation.

Here are a few things to check:
1. you're taking your readings at the proper temp!
2. You are mixing your wort VERY WELL before you take your OG sample.
3. Check your hydrometer in 60F water and ensure it reads 1.000

Dennis1979 · 10-20-2008, 04:42 PM

1. I am adjusting for temp. That is to say, yesterday's reading was at a temp of 70 degrees so I added .0014 (add .001 for each 7 degrees over 60). So to be exact, my reading was 1.060 at 70 degrees so adjusted OG is 1.0614.

2. Hmm, I was mixing the wort the whole time during cool-off but I didn't necessarily mix it right before taking the reading. A few minutes may have passed.

3. I will check my hydrometer tonight. Good point. I am assuming it is correct since it's new but probably made in China so who knows.

TeleTwanger · 10-20-2008, 04:49 PM

whats the recipe? Usually recipes give higher efficiency then most people get not lower. Maybe you're getting really high extraction from the grains....If it's all extract then there's not much guess work.

Dennis1979 · 10-20-2008, 04:56 PM

Quote:

Originally Posted by TeleTwanger

whats the recipe? Usually recipes give higher efficiency then most people get not lower. Maybe you're getting really high extraction from the grains....If it's all extract then there's not much guess work.

It's a dortmunder recipe from the HBS. Its an extract with crushed grains steeped in as well. That was the first batch. Second batch is English Brown Ale.

Hoosier · 10-20-2008, 05:11 PM

Are you compensating for water loss during your boil?

Dennis1979 · 10-20-2008, 05:30 PM

Quote:

Originally Posted by Hoosier

Are you compensating for water loss during your boil?

Well, before I took the reading, I added water to the wort to get up to 5 gallons in total.

ifishsum · 10-20-2008, 06:33 PM

I've had that happen to me a couple of times, I just added a bit more top-off water (say up to 5.5 or 5.75) to compensate somewhat. If you have room in your fermenter to handle that, it seems to work for me - in fact I'll often use an extra 1/4-1/2 lb of extract in my large PM recipes, that way if I get low efficiency on the mash it makes up for it and if it's a little high (it usually is) I top off with a little extra water to get back in range.

This may not be the right approach, but it seems to make sense to me and I've been happy with how my brews have turned out so far.