Unlike tomatoes, peppers and other crops, it can be really difficult to tell if they are ready to pick.

Commercial growers often target a percentage of dry matter. This means taking samples, drying them and comparing the weights before and after. Optimal picking is when the wet hops are 4 to 5 times heavier then the dry matter. This involves taking lots of samples and isn’t practical for most home growers. Instead, we often look for changes in the color, texture, or even sound of the cones. Unfortunately, these methods aren’t completely accurate and people often end up picking the unripe hops early. Unripe hops have immature lupulin glands and will not have the proper aroma and bitterness levels.

Here is a better way: grab a microscope!

Unripe hops

Lupulin glands appear as a yellow powder and are sometimes confused with pollen. The glands start as cup shape shown here:

Ripe hops

When ripe, the glands will be plump. Here you can see the glands fully engorged with the oils that give hops their full flavor:

Unripe brown hops

Hops can turn brown for any number of reasons – so, this is not a good indication of ripeness. Here is a cone from a plant that was under watered. The glands indicate that the cones are not ready to pick (and may never be).

So, when is the best time to pick?

You really need to look at the glands from cones on different parts of the plant. Often, the cones near the top of the plant will ripen first – sometimes by a matter of weeks. I usually wait until the majority of cones have fully engorged lupulin glands. The tips of the older cones may start to turn brown, but this is okay as long as you don’t wait too long.

The microscope

This pictures were taken with my cellphone and a $10 DIY microscope I built: