Getting right Gravity and another question

[widdleavi]

Question #1 - How important is it to get the Gravity to match exactly what the recipe calls for ? Then if it is off how to you get it to match ?

Question #2 - How do measure out hops ? What I mean is lets say the recipe cals for 1oz of type of hops at alpha 10% and when I order the hops the one the comes is alpha 13%. Do I still use the full 1oz or do I put in less since the percentage is higher ?

Thanks in advance for any help

 

[neosapien]

quick and dirty formula for IBU: (ounces of hops * %AA * %utilization) / (gallons of wort * 1.34)

utilization can be figured as roughly 27% for 90-min boil, 25% for a 60-min, 15% for a 30-min, and 5% for a 15-min. Those aren't entirely accurate, but they're pretty close.

I use a triple-beam to weigh mine out. And if the difference is just 13% instead of 10%, I'm of the opinion that you just go ahead and dump the full ounce in there.

 

[frazier]

Welcome to HBT!

1. If I get within +/- .005, I consider that a success. RDWHAHB, and all that. If it's way too high, I just add water and get more beer. If it's too low, I can add some extract. A pound of DME boiled in a quart of water, cooled and added, raises the gravity by 6 points or so.

Cheers!
2. Make friends with a recipe calculator - Hopville, TasyBrew, Brewmasters Warehouse, and others, have free online calculators. There are programs you can buy for $20 or so that many people swear by. Take your pick.

 

[frazier]

Also: Important to realize that a recipe based largely on extract will inevitably come out right on target, as long as you remember to add all the ingredients and proper amount of water. If the reading is way off, it's probably operator error. It happens a lot!