The Barrel House is a location present within The Minish Cap. It is positioned within the eastern section of the Minish Village. This location houses a Minish Researcher who is working on ways to improve Pico Blooms and it is also where Link receives the Jabber Nut early in the game. Link can visit this house multiple times over the course of the game after the Jabber Nut is obtained and each time the researcher requests Link to bring him a substance of some sort. Bringing said substance allows him to make a Pico Bloom open up and a new type of Picolyte will be available to purchase from Beedle in Hyrule Town.
Early on during the events of the game when Link first visits the Minish Village, it becomes apparent to him that he can't really understand what any of the Minish inhabitants there are saying; however, soon he meets the Minish named Festari who actually can speak Hylian. At first surprised because he hadn't seen a human in a long time, Festari soon explains to Link that in order to understand what everyone else is saying, he should go obtain and eat the Jabber Nut that is located within the Barrel House. Upon doing this, Link can understand everyone else now and as such is able to continue onwards in order to track down the Earth Element.
Pico Blooms Grown Here
The Minish Researcher tells Link that he needs some Milk to help enhance these blooms. With that known, Link exits the village and after growing back to normal size, heads off towards Hyrule Town, where the friendly Malon is selling Lon Lon Milk to anybody who may want some. After purchasing some of this from the kind girl, Link returns to the Barrel House and gives the Milk to the researcher. After this, Link leaves and upon returning sometime later, the Yellow Pico Blooms open up and the Minish thanks Link. This makes Yellow Picolyte available for purchase from Beedle in Hyrule Town.
The Minish Researcher tells Link he needs some Hot Spring Water to enhance these blooms. With that known, Link exits the village, and after returning to normal size, he heads off to Mt. Crenel to obtain some of this. Arriving at the mountain's base, Link shrinks and soon arrives at a source of this piping hot water, quickly filling up one of his bottles. With it, Link soon returns to normal size and hurries off back to the Barrel House. Supplying the researcher there with this hot water, Link leaves and after waiting a few moments, returns to see the Blue Pico Blooms open up. Once again, the Minish there thanks Link for helping him. This makes Blue Picolyte available for purchase from Beedle in Hyrule Town.
The Minish Researcher tells Link he needs a Red Potion to enhance these Blooms. With that known, Link exits the village, and after returning to normal, heads off to Syrup the Witch's hut because if a certain Kinstone fusion was made earlier she would have now brewed up such a concoction. After purchasing a bottle of this stuff from the Witch, Link returns to the Barrel House and gives it to the researcher. As with the previous blooms, Link then has to leave for a while to allow the enhancement to carry through, and upon returning, he witnesses the Orange Pico Blooms open up and the researcher thanks him for all the help he has provided. This makes Orange Picolyte available for purchase from Beedle in Hyrule Town.