Table 1.

Schematic chart of experiments by Plackett-Burman design

Order	Total solid contents of concentrated decoction (%)	Mass ratio of ethanol to concentrated decoction (g/g)	Ethanol concentration (%)	Ethanol adding time (min)	Stirring speed (r/min)	Refrigeration temperature (°C)	Refrigeration time (h)
								DOE 1	50	3	89	30	400	25	12
DOE 2	30	3	95	10	400	25	36
DOE 3	50	1	95	30	200	25	36
DOE 4	30	3	89	30	400	5	36
DOE 5	30	1	95	10	400	25	12
DOE 6	30	1	89	30	200	25	36
DOE 7	50	1	89	10	400	5	36
DOE 8	50	3	89	10	200	25	12
DOE 9	50	3	95	10	200	5	36
DOE 10	30	3	95	30	200	5	12
DOE 11	50	1	95	30	400	5	12
DOE 12	30	1	89	10	200	5	12
DOE 13	40	2	92	20	300	15	24
DOE 14	40	2	92	20	300	15	24
DOE 15	40	2	92	20	300	15	24