Gravity issues

[mattjgalloway]

Hey everyone.

I'm having gravity issues with all of my brews. I usually overshoot the OG by a couple of points. And then the FG is overshot also by a couple of points.

Now I may be able to answer my own question, but wanted to check here and see what people think.

I have my volumes all set up for a final fermentation volume of 4.5 litres, but I'm very often nearer to 4 litres. It's hard to say for sure because my measurements are very crude. I don't have a scale on the pot I use as my kettle. But when I put into my FV which is a 1 US gallon BBS, I end up with just a small amount left after filling it. 1 US gallon is 3.8 litres.

So maybe I need to adjust down, or add more water?

Obviously the best bet is getting a kettle with measurements on it, which I plan to do soon!

Thoughts?

 

[RM-MN]

My kettle has no scale on it but I have a tape measure. It's pretty easy to find the volume if you know the depth of the wort if the kettle has straight sides.

 

[Bellybuster]

Without knowing your volumes you haven't a chance of hitting targets.
Why would you shoot for 4.5 litres if you only have a 3.8 litre fermenter

 

[stonebrewer]

I would add water to hit your OG if that is important to you. I will say it is not important to me, as long as I am only overshooting a couple of points. It should make very little difference in taste and should only mean a tad bit more alcohol in the final product. My advice is to not worry about gravity as long as you are in the range of, say, +/- 0.005. Cheers!

 

[C-Rider]

Get a measuring cup that holds say 2 cups. Fill it and pour the water into your boil kettle.
Get a piece of PVC pipe or use your tape measure and make on the PVC or note paper if using the ruler.
Add 2 more cups and repeat until you have a "measuring stick" or the volume information from the tape measure.

Bingo you now know exactly how much you have.

 

[mattjgalloway]

Why would you shoot for 4.5 litres if you only have a 3.8 litre fermenter

Great question! Answer is two-fold. First, I messed up with 1 US gallon being 3.8 litres, whereas 1 imperial gallon (what I'm used to) is ~4.5 litres. And I was finding that it ended up just about right for my fermenter. But the fermenter is 3.8 litres, so that's why I started wondering about my process and asking this question.

My advice is to not worry about gravity as long as you are in the range of, say, +/- 0.005. Cheers!

I'm seeing +- 0.02 though. Usually on the plus side, apart from once when I forgot to mash out and I got negative side. And usually +0.01 but once it was +0.02.

Get a measuring cup that holds say 2 cups. Fill it and pour the water into your boil kettle.
Get a piece of PVC pipe or use your tape measure and make on the PVC or note paper if using the ruler.
Add 2 more cups and repeat until you have a "measuring stick" or the volume information from the tape measure.

Bingo you now know exactly how much you have.

This is a great idea! I'll do this. So silly that I didn't think of it myself. I did a make-shift one which was a crude notch on a wooden spoon at 4.5 litres. But it's just one notch and I find it hard to really tell what's going on with just that 1 notch. I think I'll do the measuring stick idea with a tube.

 

[mattjgalloway]

So... it turns out that my hydrometer is reading +0.002. Which is, umm, what my OG and FG are out by usually! I've gone back and corrected my values everywhere and I'm feeling pretty good about my attenuations, and more realistic on the efficiencies now!

I still need to watch the volumes, but I suspect I'm actually closer than I thought.

Also - I've been using the tape measure method on the last couple of brews and that's helped me be more accurate for sure!