Just finished a batch and the targer OG was 1.054 and achieved a 1.060 which is a little high for the style. Have never added water to correct. How much would you add? Have 5.2 gallons in the fermenter. Plan to cool down to 50 degrees over night and pitch yeast in the am in which would add cooled boiled water but don’t want to add too much. :cheers:

If you are supposed to have 5.5 gallons at 1.054 that is 297 gravity points (5.5*54)

The gravity in the kettle does not change (nor do your gravity points), so if you have 5.5 gallons at 1.060, that is 330 gravity points. 330 divided by your final target gravity of 1.054 (330/54) is 6.1 gallons, so you need to add .6 gallons.

Clear as mud?

My pre-boil wort was 6.5 gallons. Would the amount be the same?? :cheers:

If you are supposed to have 5.5 gallons at 1.054 that is 297 gravity points (5.5*54)

The gravity in the kettle does not change (nor do your gravity points), so if you have 5.5 gallons at 1.060, that is 330 gravity points. 330 divided by your final target gravity of 1.054 (330/54) is 6.1 gallons, so you need to add .6 gallons.

Clear as mud?[/quote]

Excellent info. :cheers:

It works the same way. It took me a few reads to wrap my head around this, but it is an INCREDIBLY useful back of the envelope calculation once it makes sense to you.

Another example:

If your preboil volume is 6.5 gallons, and your pre boil gravity is 1.052, that is 338 gravity points in the kettle. That cannot change, even with boil off (WATER boils off, SUGARS do not).

So, if you are going to boil for an hour and you know your boiloff/evap is 1gallon/hour, you know you are going to end up with 5.5 gallons at the end of the boil. Keeping your 338 gravity points (again, sugar can’t evaporate), you know that your post-boil gravity will be: 338/5.5, or 61, or 1.061.

If you are shooting for an OG (Post-boil) gravity of 1.054, keeping with our example above, you STILL have 338 gravity points in the kettle. So, you need additional volume. How much? 338/54 = 6.2 gallons. 1gal/hour boil off, you need to have 7.2 gallons at the START of the boil.