Stevia rebaudiana

stevia-05Stevia, also known as the Sugar Plant, has leaves that are very sweet yet calorie-free.  The active compounds responsible for the sweetness are the steviol glycosides (mainly stevioside and rebaudioside).

Apr 7, 2016 = Day 0.  Plant started from seed (Park Seed Co.).  Seeds sowed in 1.5-inch rockwool cube in 2-inch net-pot.  Moistened with dilute fertilizer solution: 1.2 mL (1/4 tsp) Dyna-Gro Liquid Grow, 0.8 mL pH Down per gallon of tap water.  Nutrient concentrations (in ppm):  N 22, P 29, K 16, Ca 6, Mg 1.6, S 0.2, Fe 0.3, Mn 0.2, B 0.1, Zn 0.2, Cu 0.2, Mo 0.003, Ni 0.0003, Co 0.005.  pH = 6.0.

Apr 11 = Day 4.  Plant germinated, placed directly under a fluorescent light (2 ft. T8 bulb, 17W, 6500k) for 16 hours per day.

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Apr 19 = Day 12

Apr 22 = Day 15.  Installed plant into 3.5-gallon bucket.  Hydroponic solution composed of 3.5 gal (13.2 L) tap water, 53 mL 250x Masterblend 4-18-38, 53 mL 250x calcium nitrate, 53 mL 250x magnesium sulfate, 0.7 mL Dyna-Gro Pro-TeKt, 3.5 mL pH Down.  (This solution is equivalent to 3.5 gal water, 7 g Masterblend, 7 g calcium nitrate, 3.5 g magnesium sulfate).  Nutrient concentrations (in ppm):  N 103, P 95, K 202, Ca 100, Mg 29, S 34, Fe 2.1, Mn 1.1, B 1.1, Zn 0.3, Cu 0.3, Mo 0.05, Si 4.  pH = 6.0.  Plant moved to indoor grow room, receiving 8 hours LED grow light per day, plus 3 hours sunlight per day.

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May 2 = Day 25
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May 26 = Day 49
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Jun 16 = Day 70
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Jul 6 = Day 90

Jul 13 = Day 97.  Entire plant was harvested, cut at the base.  Total fluid used = 1.5 gallons.  Final pH = 5.0.

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Jul 13 = Day 97.  Root system of Stevia plant.

To dry the leaves, plant was hung upside-down in a well-ventilated room.  After a week, the dried plant leaves were crumbled and stored in an airtight container.

To extract the steviol glycosides from the dried leaves, I followed the following procedure:

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Put the dried, crumbled stevia leaves into a glass container.
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Add 1 cup vodka (I used SKYY vodka).  Cover and let it sit for 36 hours.
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After 36 hours, filter out the leaves using a funnel and a coffee filter.
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Using a low heat setting, evaporate off the alcohol with constant stirring (takes about 20-30 minutes).  Don’t let it come to a boil, or it will burn the extract.
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Store the finished sweet extract in an airtight container in the fridge.
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