Drying cannabis post-harvest determines the final quality, potency, and flavor of the finished product. Freshly harvested flowers contain a high percentage of water, which must be slowly and carefully removed to prevent mold growth and degradation. This preparatory phase preserves delicate cannabinoids and aromatic terpenes, which are responsible for the plant’s effects and fragrance. Achieving the correct moisture level prepares the buds for the subsequent curing process, which further refines the sensory characteristics.
Optimal Environmental Conditions for Hanging
Controlling the environment during the hanging phase is the most important factor, as it dictates the rate of moisture loss. The ideal temperature range for a drying space is between 60 and 70 degrees Fahrenheit (15-21°C). Maintaining this cooler temperature minimizes the volatilization and degradation of heat-sensitive terpenes. Higher temperatures cause buds to dry too quickly, resulting in a harsh smoke and a “grassy” flavor due to trapped chlorophyll.
The relative humidity (RH) should be kept within a target range of 45% to 55% to facilitate a slow, controlled dry. If the air is too dry (below 40% RH), the outer layer of the buds can become brittle and seal in moisture at the core, leading to uneven drying. If the humidity exceeds 60% RH, the risk of mold and mildew proliferation increases dramatically.
Gentle, passive air circulation is necessary to exchange the moist air evaporating from the plants with fresh, dry air. Fans should never blow directly onto the hanging material, as this creates hot spots and causes rapid, uneven drying. Drying must occur in complete darkness because exposure to light, especially UV rays, accelerates the degradation of cannabinoids. Monitoring these conditions consistently with a reliable thermometer and hygrometer is necessary to prevent significant fluctuations.
Typical Duration of the Upside Down Hang
The time required for cannabis to hang upside down typically falls within a window of 7 to 14 days. The overall goal is to remove approximately 75% to 80% of the plant’s initial water content, leaving sufficient internal moisture for the curing phase.
This timeline is highly dependent on several factors. The density of the buds is a major variable; thick, compact flowers require more time to dry than loose structures. The trimming method also plays a role: wet-trimmed flowers (leaves removed immediately after harvest) dry faster than dry-trimmed material, which slows moisture loss and often results in a superior flavor profile.
Thicker stems and larger sections also extend the drying time because they hold more water and act as a moisture reservoir. Growers should aim for a slower dry toward the 10-to-14-day end of the spectrum, as this extended period helps ensure the slow breakdown of chlorophyll, which leads to a smoother smoke.
Assessing Readiness The Stem Snap Test
The most common physical method to determine if the hanging phase is complete is the “stem snap test,” which checks the remaining moisture content. This test involves gently bending a small, representative branch, about the width of a matchstick. If the stem is ready, it will snap cleanly and audibly rather than simply bending.
The goal is to confirm that the material is pliable but no longer damp. If the stem bends without breaking, too much moisture remains, and the buds are not yet ready. The small branches attached to the individual flowers should also snap, though the largest main stem may still retain slight flexibility.
Once the snap test is passed, the buds should feel dry and slightly crispy on the exterior but still possess a small amount of sponginess when lightly squeezed. The ideal internal moisture content for transitioning to curing is between 10% and 12%. A moisture meter can be used to confirm this range, offering a more objective assessment than the manual snap test. Passing this readiness test signals that the buds are prepared for trimming and the subsequent air-tight curing process.