Basket is home from the Nether with blaze rods, soul sand and nether wart, and this episode puts them to work. First a nether wart farm, then a brewing lesson, then a long fight with redstone to make potions at the push of a button.
A wart farm upstairs
The tour starts in the middle area of the base. Stairs now climb all the way up, the walls are wider, and the plan is small rooms branching off as it rises. New sorting chests hold books, enchanted odds and ends, stone, monster drops and "the nether supplies."
The first of those side rooms becomes the nether wart farm. Basket digs it out, lines the walls and ceiling with brick, and makes the whole floor soul sand. A craft of iron bars turns out more than expected ("Oh wow, 16"), and they become a window looking into the main entryway. Glowstone goes into the ceiling. The old pick was "basically broken down," so it now hangs in an item frame and a new Efficiency IV pick takes over.
By the next cut there is almost a full stack of wart, "plenty for now."
Brewing 101
Down by an infinite water source, Basket covers hoppers first: they move items from one container to the next, and powering one with a lever stops it. Then the brewing basics. Water bottles plus nether wart make awkward potions, which do nothing. Add a Glistering Melon and they become Potions of Healing. Add gunpowder and they turn into splash potions. Those are for the zombie grinder, because healing hurts zombies: "I can throw the healing potion, kill them all, get the experience."
Order matters. Put the melon in before the wart and you get a mundane potion, which Basket usually throws away.
One button, three ingredients
The goal is three hoppers fed from three chests, one each for wart, melon and gunpowder, releasing one item at a time in the right order when a button is pressed. It does not go smoothly. The first test lets only the wart through. Then the melon arrives first, "because it has less to travel." Then a block powers its neighbor and makes "an infinite loop." Extra repeaters fix that one. "Redstone things always turn into more complicated than planned."
After a rebuild with the three hoppers side by side, the ingredients finally drop in the right order.
A cobweb timer
The last step is a long delay so the finished potions get pulled out and fresh water bottles go in. A first try with repeaters is nowhere near long enough. The wiki says a brew takes about 20 seconds, and Basket wants about 30 seconds of delay, "a pretty long delay for just repeaters."
So Basket puts a Silk Touch book on a pair of shears (the tooltip reads Silk Touch I, Unbreaking II) and heads off to a mineshaft for cobweb. The wiki says an item takes about 24 seconds to drift through it.
Back home, a block of cobblestone gets shot into the web, sinks, trips a tripwire, and that signal swaps the bottles. The cobblestone then cycles back so it never runs out.
First batch
With the brewing sped up in the edit, the test works: splash potions come out and three new water bottles go in. The output chests ended up sunk into the floor, which Basket can live with. A second brewing stand may come later.
Then one extra piece at the grinder. At level 16, with "only sixty or so" zombies inside, Basket throws a splash potion of healing down. "They all die," and the level reads 24 afterward. The catch is gunpowder. There isn't much, so the next plan is creeper hunting in the desert. The episode ends with Basket alive at home by the grinder.