Picolyte

Picolyte is a mysterious juice-like stuff that Beedle sells in The Minish Cap. The drinker of Picolyte has the rate of finding certain items increased, such as Kinstones, Recovery Hearts and Rupees. This most significantly affects the rate of finding certain items in grass. The best place for this is in the field to the west of town. The effects of Picolyte wear off after approximately 30 seconds.

For Beedle to start selling Picolytes, Link must first clear the dust from the area where Beedle is going to set up shop. He can do so with the Gust Jar. White, red and green varieties are available immediately.

Picolyte is made by a Minish Researcher from Picoblooms. To enable the manufacture of the blue, orange and yellow varieties, Link is asked to assist him by bringing hot spring water, milk, and potion. After giving the researcher an item, Link must go to a distant area and then return for the Picoblooms to blossom.

Types of Picolyte
There are six types of Picolytes that you can buy in The Minish Cap each with their own unique abilities:

Usefulness
In terms of cost, some Picolytes are more useful than others. White Picolyte will probably get Link more Kinstones for less than if he just bought them. Yellow Picolyte is only profitable if Link works fast to find Rupees and likewise for Green Picolyte. The other Picolytes are, arguably, a waste of money.