Pour the thistle seeds into your blender. Blend the seeds till they make a paste. You can also use a grinder for the purpose. Empty the contents of the blender into a canning jar. Make sure that the jar has already been sterilized. You can sterilize it by boiling them in a pot for around ten minutes so that all the germs are removed.
Add alcohol and water:
To the jar with the blended seeds, add a cup of alcohol and 1 cup of water. Make sure that the alcohol you use should be 100 proof. Stir with a clean spoon so that the ingredients mix together.
Once you stir in the ingredients well, place the lid on the jar and also secure it strongly. Now choose a place around the house which is both cool and dark.
Let the seed mixture stay in the place for 4-5 weeks. Keep shaking the jar regularly daily so that seeds mix in and the flavour is enhanced. Prepare another mixture of one cup alcohol and one cup water in another jar. Use this reserve to fill up the first jar whenever the solution level it inside it falls. Make sure the seeds are never exposed and remain in the solution.
After the prescribed time is over, pour the mixture into a sieve and drain the liquid into a jar. The liquid that passes through the sieve is your extract. Store it in sealed containers and use accordingly.