Harvest Timing and Dry Matter / by Kathy Dunbar

Harvest is in full swing at Freestyle Farms, with the Motueka coming in smelling strongly of tropical fruit (and awesomeness!!!).

Harvest timing has a significant impact on flavour, aroma, acids, and HSI.  Beginning with next year’s harvest, picking times for each varietal will be selected to maximize the naturally strong tropical fruit, citrus, floral and pine flavours common to the hops we grow, with a clear objective to maximize flavour and aroma.  We believe that maximizing aroma and flavour, rather than weight, acids or HSI, is crucial to producing an exceptional hop.  That said, we are quite open to harvesting objectives that meet specific goals.  We plan to further explore optimization around harvest timing and the intended hot side, cold side or dry hopping use of the hops.

To plan harvest timing, we use a combination of dry matter measurement, in-field sensory analysis, visual indicators, historical harvest data, plant condition, location (soil type) and experience.  After exhaustive research we have concluded that dry matter analysis and in-field sensory analysis (systematically gathering rubbing impressions) are the most accurate predictors of flavour and aroma in processed hops.

Dry matter analysis is simply a measure of the average moisture content of the sampled hop cones.  This moisture content is highly predictive of the state of cone maturity, and by extension the state of all the acids and aromatic compounds in the hops.  Generally, we will target ~23% dry matter for harvested hops, although this varies based on varietal from ~22% to ~26%.  The variation is primarily driven by cone structure, with particularly dense hops like Cascade or Green Bullet picked at the high end of the range.  Below I've pasted the dry matter results from our sampling earlier this week to give you a better sense of the numbers.  Block 7 was picked today and Block 13, 9 and 12 will follow shortly.

To systematically gather in-field sensory analysis, we have developed an app that allows us to gather frequent and standardized data about aroma impressions.  We are planning to use everyone who visits us this year to help build a broader sample of impressions and make improvements to our process prior to next year’s harvest.  The primary use of sensory data will be to avoid prematurely harvesting hops that still exhibit strong grass or herbal notes (unless that’s what you’re after :-)).  As we gather data, and gain experience with our blocks, the hope is that we can extract additional insights from the in-field sensory data.

We look forward to working with all of our partners to continue improving our harvest timing.  Below are some photos of the harvest action, some Motueka bursting with lupulin, our new equipment chucking out leaves, and dried hops conditioning before going into bales.

Cheers!
Dave