I am making the leap to full all-grain brewing
Nice.
I know alcohol content is the difference between original and final gravity, but if I wanted my beer to have a certain alcohol percentage, say 5%, how could I ensure this?
I hate to sound like Captain Obvious here, but you set target original and final gravities. Of course setting targets and hitting them are two completely different matters. But that's part of the fun!
For example you want 5% alcohol.
You may look at a hydrometer chart and notice 6% potential at 1.045 and 1% at 1.008.
Or 7% potential at 1.052 and 2% at 1.0015.
Using formulas, experience, or a tool like Beersmith, you set up a recipe.
If you were using extract you would be at the mercy of whoever mashed the grain as to what ratio of fermentable to non-fermentable sugars you had to work with.
But with all-grain you now control this with the temperature of the mash.
The higher the temp, say 155 range, the higher the final gravity and more body or mouthfeel.
The lower the temp, say 145 range, the lower the final gravity and more watery beer.
There is a tradeoff. Lower temps take longer to convert.
Then there is the yeast. Some yeasts eat more available sugars than others. They call that attenuation.
Then there are the grains. Crystal malt will add body without much fermentable sugars. A pound can increase the final gravity by .005 or more without adding that much alcohol.
There's a lot to it. But don't be daunted.
Not only do you learn from your mistakes, but you get to drink them too!
