Lemon Thyme (Steam/Hydro)

In this experiment I used  fresh Lemon Thyme (Thymus x citriodorus). The first was was steam distilled, meaning the plant material was in the column and only steam passed through. The second was hydro distilled, meaning the plant material was put directly in the water in the pot and boiled.

In order to have a meaningful comparison it was imperative that I limited the variables; therefore the plant material was harvested and immediately split into equal weights for each still.  The same water source was used for both the steam and hydro distillation.  I kept the heat, flow rate and distillation length as close as possible.  A sample of essential oil, hydrosol and water left behind in the pot were collected and sent to Pyrenessence Laboratory in France for GC-FID analyses.  The following are the results.

Still 1: Steam Distillation

Plant Material Weight (in kgs):  2.68kg  (5.9 pounds)  Fresh Weight
Size and Type of Still:   30 Liter Copper Column Still
Amount of Water in pot:  12 Liters   pH: 6.1
Fire On:   11:16
Hydrosol First Drip:   12:01
Fire Off:  13:25
Essential Oil Yield:  4.2 ml
Hydrosol Yield:  1700 ml
pH of Water left in pot:  6.3 pH clear,  yellowish  Total volatiles in Pot Water: 5 mg/L

Time: pH Hydrosol  Temperature: Flow Rate: (ml/min)
12:22 6.0 24C 40ml/min
12:40 5.7 39C 44ml/min
12:55 5.9 19.5 22ml/min
13:15 5.5 18.8 20ml/min

The plant material was harvested and weighed.  2.68 kg was packed firmly in the column and 12 liters of well water was added to the pot.  When the distillation was finished samples were collected.

The following are the results of the analyses.

Still 2: Hydro Distillation

Plant Material Weight (in kgs):  2.68kg  (5.9 pounds)  Fresh Weight
Size and Type of Still:   30 Liter Copper Pot Still
Amount of Water in pot:  12 Liters    pH: 6.1
Fire On:   11:16
Hydrosol First Drip:   11:56
Fire Off:  13:25
Essential Oil Yield:  2 ml
Hydrosol Yield:  1700 ml
pH of Water left in pot:  5.9  dark brown         Total volatiles in Pot Water: 40 mg/L

Time: pH Hydrosol  Temperature: Flow Rate: (ml/min)
12:25 5.9 26.8C 48ml/min
12:40 5.8 33.6C 26ml/min
12:55 5.9 18.4C 22ml/min
13:15 5.6 18.1C 26ml/min

The plant material was harvested and weighed. 2.68 kg was added to the 12 liters of well water in the pot. When the distillation was finished samples were collected.

The following are the results of the analyses.

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