What do they mean when they use the word yield? Why are yields on dry flower sometimes upwards of 20% when only 3% of Fresh Flower? What is yield to Rosin?
When we refer to “Potency” in “Botanicals,” we mean either the total THC in the sample or, more typically, the Total Active Cannabinoids. This is because all cannabinoids generally affect the body in many ways and interact with one another. These effects are best left for another discussion, the point being what is noted.
There is typically a big difference in potency between Fresh Flower and dry flower. This is because dry flower weighs less in volume. “Wet” or “Fresh” flower typically weighs five times more than dry flower. If we had one gallon of fresh flower weighing 1,000 grams once dry, the same gallon of the same flower would probably weigh 200 grams.
Fresh Flower weighs about five times that of Dry Flower
Dry Flower = +/- 20% wet moisture content
The density of Fresh Flower is about 0.7-0.8 pounds per gallon or 400-500 grams per liter.
In the gallon of flower scenario above, if the gallon of flower contained 70 grams of total active cannabinoids (TAC), the potency of the sample would be 7%. When flower dries, for the most part, only water evaporates. Trichomes are mostly impermeable, and thus most of the 70 grams of TAC in the fresh flower would still be present in the dry flower. Notice that 70 grams of TAC in a 200-gram sample is thus 35% TAC.
70 / 1,000 = 0.07 or 7%
20 / 200 = 0.35 or 35%
This makes total sense when we realize that potency testing is analyzed based on weight, not volume. OK, so now we know what TAC refers to and know to calculate it by weight. We also know that wet flower is about 5 times heavier by volume than dry flower.
What about hash yield when extracting for solventless? How is that measured? When extracting for solventless IWE or CWE, etc… we need to analyze the weight of the flower input versus the dry hash output. In a device like the Mesclatore Solventless, when washing flower, we would load, say, 20,000 grams of fresh flower. If the flower were dry, we would only fit 4,000 grams. The volume is the same, the TAC is similar, but the weight is different.
Once trichomes are extracted, we dry the slurry and then take the weight of the dried hash. This is because water has no commercial value and is thus irrelevant. If the fresh flower wash yields 1,600 grams of dry hash, our yield is 8%. In this example, we expect roughly 1,600 grams of dry hash from the dry flower if it’s the same cultivar. The yield, in this case, is 40%. Note that we got the same amount of hash but a different yield. This is due to dry flower weighing less.
1,600 / 20,000 = 0.08 or 8%
1,600 / 4000 = 0.40 or 40%
Typical Fresh Flower Yields: 3-8%
Typical Dry Flower Yields: 8-25%
Now that we have dry hash and plan to press and produce Rosin, how do we calculate that? The 1,600 grams in the example above get pressed and weighed. The total rosin produced is, say, only 960 grams. At this point, we say the “Yield to Rosin” is 60%.
960 / 1600 = 0.6 or 60%
Typical Rosin Yields: 60-90%
But what gives? What happened to the 640 grams we just lost? For the most part, they weren’t there in the first place. The vast majority of extractable cannabinoids are on round bulbous trichome heads. Stalks usually have no cannabinoids, mainly protein, fats, and other insoluble materials. Although this was extracted as hash, it does not add much to TAC. Thus the 640 grams did not melt into rosin and did not extract as there wasn’t much to extract in the first place.
In the example above, if our rosin has a TAC of 85%, we would expect the hash to have a TAC of only 51%. This highlights the importance of extract quality and is why higher-purity products sell for more. There is more medicine there and less filler. Since stalks do not quickly melt, the low quality of a product shows up as residue and is evident to the end user. There is no hiding from the truth; Fire is Fire.