Ive read many recipies and they dont specify any need to open the jar on ocassion, they just say to put them in a closed jar and store in a dark place for 4 to 8 weeks.
The reason I dont open the jar is because alcohol evaporates and diluted alcohol will make the process take longer.
When I extracted THC in alcohol the process was the same, never opened the jar until the 6 weeks were over. Then you could filter the alcohol and leave it in an opened jar for alcohol to evaporate and make the THC solution more concentrated.
I dont think that last part is necessary for tribulus though.
That THC extraction process bit, brought back a lot of memories… I miss Lycaeum.org