Thanks everyone for the feedback.
I think that I'm going to get a refractometer. I estimate that acquiring an initial sample to fill a test vessel and again a final sample I would loose a whole bottle of my brew just for the knowledge of the achohol content. I figure that the alcohol content is pretty much out of my control. I would rather just enjoy my beer as it is.
At my level of brewing NB extract kits its beyond my skills to tweak the recipe. Maybe in the future.
I feel your pain on losing brew to measurements. I used to split a 2.5gal batch with 3 friends and wasn't a fan of ending up with 4–5 bottles after waiting a month!
There are ways to solve this for a future brew:
1. Adjust your calculated losses to factor in measurements. This means you will start with more water initially. Considering the volumes in question, the effect on final ABV or amount of grain used to compensate is minuscule if even practically measurable.
2. Sanitize your siphon or wine thief, and your hydrometer, and your testing tube. Pour the sample back in when done–slowly. (or add it to the bottling bucket) You don't want to introduce too much oxygen if any at this point. This isn't ideal, but it will do in a pinch until you get more experience, or employ #1 above, especially if you will likely drink the batch in less than 2 months.
Here are a few other tips:
• A big loss you need to factor in is fermenter trub. (and yes, I dump the entire kettle, but loss there can be equally significant if you don't.) I've found it to be pretty consistent for my system at 10%, which means if I want 2.5 gallons packaged, I plan for racking 2.75gal to fermenter, 5gal requires 5.5gal to the fermenter, etc.
• I now have spigots on my fermenters for samples and transfers. (BigMouth Bubblers and BSG Buckets)
• I switched my sample tube to a smaller one to save on beer loss. (some need as much as 10–12 ounces! Mine from NorthernBrewer works fine with less than 4. BrewingAmerica sells a fancy glass version that is likewise judicious with sample size if you want a really nice instrument.)
• To be consistent with your sample loss, put your hydrometer into your sample tube and add water until it floats and then a touch more. Mark the water level on the tube with a permanent marker. Remove the hydrometer and measure the amount when you pour it out. (use that in your loss calculations) Next sample, you know exactly where to stop filling the tube.
• During fermentation, I take samples every 24hours in a shot glass (usually less than half) and chill that in the fridge for an hour or so to let it clarify, then take a refractometer reading as well as make aroma and tasting notes in my logs. (chilling helps drop some yeast out of the sample for a clearer reading on the refractometer)
• I try to do Fast Ferment Tests on every batch to have a more true FG target.
• Only when I hit the same (or really close) FG as the FFT for at least 72 hours, I chill and then package. I also started taking pH and wait for that to stabilize too. (a bit more advanced, I admit)
• When I'm packaging, I take a hydrometer reading before transfer for official FG. (I've long since factored in the sample amount as a loss so I just toss it now—or drink it! It is still your beer, just not carbed up.)
As several pro-brewers have told me, refractometers are 'close enough for government work' when determining gravities for ABV, especially if you use an adjustment formula 'with alcohol present' and/or de-gas the sample before measuring. But if you're a stickler, the above tips should get you a full batch in your belly.
