I have now been brewing for about a year and have a consistent problem. I am doing full volume extract boils. I start with around 6 gallons. End up with 5 in the pot after the boil. But when I transfer to the fermenter I try to leave the trub behind. Usually I then end up with less than 5 gallons. If I add water to top up I end up with a low OG. Am I doing something foolish? It’s not a tragic issue, but it just bugs me that I cant seem to get the full 5 gallons.
The kits are designed to have 5 gallons of wort at the desired gravity at the end of the boil. What you can do is increase your water at the beginning of the boil and increase your base malt extract to compensate for the added volume. So if you want half a gallon more going into the fermenter, just add half a gallon more water at the start of the boil and figure out how much DME you need to add to half a gallon to achieve your target FG and add that as a late boil addition.
Beersmith is handy for doing what Matt described above. A lot of styles you could get away adding a half pound of sugar to the boil and an extra half gallon of water with no noticeable changes and keep you in the ballpark, especially IPAs and APAs.
You could slow down your boil so you don’t boil off a full gallon. I adjust my boil and I can boil off 3/4 gal or as much as 1 1/2 gal. Actually I find a little under 5gal for kegging is optimal.
Are you making sure the water you use to top off is well mixed before you take the sample for the gravity reading? I am doing full extract boils. I start with 6 gallons and end up adding 1/4 to 1/3 gallon of top off water. I then aerate, let it sit for 10 minutes or so to let the foam on top die off, take a gravity reading and pitch the yeast. I haven’t noticed low OG. I would think if the top off water isn’t completely mixed with the other liquid in the fermenter you would get a low OG.
I use a paint mixer device on my power drill to aerate before taking my OG reading. So I mix with that for about 3 minutes. Then i allow the foam to subside for about 10 minutes and then take my OG reading. So I am rather certain that the wort is mixed well. I have to really monitor my method for my brew this weekend and see if I cn find where I am going wrong.
Once I adjusted to a lower boil, I not only saved fuel, but reduced the loss through evaporation. My top-off is much lower to get the full 5 gallons and my OG is spot on.
I think I will try that. I am always doing a pretty aggressive boil. Is there a negative associated with not doing an aggressive boil?
Lowering the boil-off isnt going to help with the gravity. He’ll just have more lower gravity wort left in his kettle. It’s the same thing as topping off. The amount of sugar remains constant. You don’t lose any during the boil, the only thing that changes is the amount of water. less water means higher gravity. more water means lower gravity. You need to add fermentables to compensate for that.
Lowering the boil-off isnt going to help with the gravity. He’ll just have more lower gravity wort left in his kettle. It’s the same thing as topping off. The amount of sugar remains constant. You don’t lose any during the boil, the only thing that changes is the amount of water. less water means higher gravity. more water means lower gravity. You need to add fermentables to compensate for that.[/quote]
Exactly. You have to adjust your recipe to achieve the desired OG and volume. Boil-off will vary by pot, vigor of boil, ambient temp, etc.
It becomes easier to hit targets as you learn your system.