Question: The first time that I brewed with whole flower / leaf hops, my more-experienced homebrewing friend said that I should have more wort than usual at the start of the boil, because the dried leaves will reconstitute and absorb liquid. I followed her directions, and I was pleased with the ultimate result. Naturally, I forgot her exact directions.

These are the [hops](http://www.oakbarrel.com/beermaking/hops_flower_chinook.shtml) that I'm using.

Is having extra wort a proper adjustment for these types of hops, and if so, how much extra wort should I have?

Answer: 
An experiment to determine wort absorption by whole leaf hope is described [here](http://www.homebrewtalk.com/f12/leaf-hop-absorption-measured-241469/). The conclusion was that an ounce of hops absorbs 0.15 quarts of wort.
Whole leaves will absorb quite a bit of your wort during boil, but it really depends on what you are brewing. Lower hopped beers (e.g. German and Belgian beers) = lower absorption, higher = higher absorption. If you are brewing a double IPA (or Imperial IPA), you may want to account for absorption by increasing your final expected quantity. 

I've often taken the mindset that for every 5 gallons of homebrew I wish to finish with, I'll add 1 gallon, making a 5 gallon batch, 6 gallons in total. 10 gallon batches become 12 gallon batches. The amount of hops and trub you end up with after primary and secondary may vary, but if you top off your fermentation bucket/carboy with 5 gallons, you will inevitably end up with less than 5 to go into kegs/bottles because of trub and yeast.

While it's my personal rule of thumb, if I plan on using whole leaf hops, or a lot of hops... Or screw it, anything in general that's excessive in hops or ABV, and want 5 gallons total output from my brew, I'll brew 6 gallons. Frankly, if I wind up with too much, and have to bottle off a few extra beers, or fill my keg to the point of overflowing, what a shame!