So I'm not saying this is the total solution to knowing when your hops are ready, but I thought it goes a bit more indepth than light paper feeling. Below is an article from Gorst Valley Hops newletter for September 2011. You can see the full newsletter at their website. Hope this helps.
(August brings thoughts of finally harvesting your hard work but the hard work is yet to begin! Rounding up labor and talking to brewers seem like the logical steps but how do you know when to harvest? Not everyone is fortunate enough to have a spectrophotometer handy but it really is the only sure-fire method for determining hop ripeness. How? Ripeness is a
misnomer. Since hops are flowers and not fruit there is no ripening but
instead there is lupulin maturation. Measuring the alpha acid content is the best indicator of maturity and therefore the most accurate determination of harvest timing. There are a few labs that will test your hops for harvest (Gorst Valley is one ) but if you only have a few plants and not enough cones to spare there is always your nose.
Hop oils are the last to develop just prior to maximum maturity. First the lupulin must be vivid yellow and clearly formed into what looks like tiny
balls. Second, the cone must have a strong odor of hops when crushed. If
there is any aroma reminiscent of cut grass or lettuce they are not yet
ready to harvest. But we need to also dispel some of the folklore around judging hop harvest maturity. If they feel light an papery they are ready to harvest. Sorry gang a few days of dry wind can make a young flower dry out and feel brittle and papery. When the bracts can be pushed back and do not return to their original position they are ready to harvest. Sorry again this can also be accounted for by a dry cone. Internal water pressure (called turgor pressure) is responsible for tissue rigidity. If you have not irrigated for a week the cones will do this anyway regardless of maturity. There is some truth to using texture and shape to judge cone maturity. As
the strobile develops a more robust strig (stem), the whole cone takes on a
square shape when viewed from the tip. Young cones tend to be very round (oblate) and dense. The bracts will also become a bit more leathery as the cone matures. Young cones will have a silky delicate texture and oftentimes be very light green to greenish-white. But dont use cone color as a guide some varieties are not very dark.)
(August brings thoughts of finally harvesting your hard work but the hard work is yet to begin! Rounding up labor and talking to brewers seem like the logical steps but how do you know when to harvest? Not everyone is fortunate enough to have a spectrophotometer handy but it really is the only sure-fire method for determining hop ripeness. How? Ripeness is a
misnomer. Since hops are flowers and not fruit there is no ripening but
instead there is lupulin maturation. Measuring the alpha acid content is the best indicator of maturity and therefore the most accurate determination of harvest timing. There are a few labs that will test your hops for harvest (Gorst Valley is one ) but if you only have a few plants and not enough cones to spare there is always your nose.
Hop oils are the last to develop just prior to maximum maturity. First the lupulin must be vivid yellow and clearly formed into what looks like tiny
balls. Second, the cone must have a strong odor of hops when crushed. If
there is any aroma reminiscent of cut grass or lettuce they are not yet
ready to harvest. But we need to also dispel some of the folklore around judging hop harvest maturity. If they feel light an papery they are ready to harvest. Sorry gang a few days of dry wind can make a young flower dry out and feel brittle and papery. When the bracts can be pushed back and do not return to their original position they are ready to harvest. Sorry again this can also be accounted for by a dry cone. Internal water pressure (called turgor pressure) is responsible for tissue rigidity. If you have not irrigated for a week the cones will do this anyway regardless of maturity. There is some truth to using texture and shape to judge cone maturity. As
the strobile develops a more robust strig (stem), the whole cone takes on a
square shape when viewed from the tip. Young cones tend to be very round (oblate) and dense. The bracts will also become a bit more leathery as the cone matures. Young cones will have a silky delicate texture and oftentimes be very light green to greenish-white. But dont use cone color as a guide some varieties are not very dark.)
