A fermented spider eye in Minecraft is a key brewing ingredient used to create some of the game’s most useful corrupted potions, including Weakness, Harming, Slowness, and Invisibility. It is especially valuable for curing zombie villagers, PvP fights, and stealth exploration, making it one of the most important brewing items for survival players.
If you’ve been playing Minecraft for a while, you already know that potions can be a game-changer. And if you want access to some of the most powerful brews in the game, you’ll need to learn how to make a fermented spider eye.
Yes, it sounds like something you’d find in a witch’s pantry. That’s because it basically is.
This guide covers everything – what the item is, how to craft it, where to find each ingredient, and what potions you can brew with it.
What Is a Fermented Spider Eye in Minecraft?
A fermented spider eye is an item used to corrupt the effects of certain potions via brewing, and is required to brew potions of Weakness.
Think of it as Minecraft’s version of a “flip switch.” It takes a potion with a positive effect and turns it into something darker. Speed becomes Slowness. Healing becomes Harming. Night Vision becomes Invisibility.
What’s fun about the fermented spider eye is it generates the opposite effect of an already existing potion. That one mechanic alone opens up a surprisingly deep layer of strategy in both survival and PvP.
It’s available across all major platforms – Java Edition, Bedrock Edition, and everything in between.
Ingredients You Need
For a fermented spider eye, you specifically need the brown mushroom and not the red one. That’s the mistake most beginners make. Here’s the full list:
- 1 Spider Eye
- 1 Brown Mushroom
- 1 Sugar
Simple on paper. A little more effort in practice. Let’s break down where to find each one.
How to Get a Spider Eye
You can get a Spider Eye in Minecraft by killing spiders and cave spiders. There’s a 1/3rd chance of players obtaining a spider eye upon killing a spider, and enchantments like Looting can help you improve these odds.
Spiders are not hard to find. They spawn at night or in dark areas underground. If you want a more consistent supply, find a spider spawner inside a cave and build a basic farm around it. This gives you spider eyes, string, and XP – all in one setup.
Witches are your next best bet if you’re fine with having spider eyes not fresh from the source. Depending on your level of looting, these magicians can drop up to 15 spider eyes at once.
How to Get Brown Mushrooms
Brown mushrooms grow in low-light environments. Check dark caves, dark oak biomes, and swamps to track down a mushroom. If you have trouble finding any of these biomes, you can also find brown mushrooms commonly in nether biomes.
A Mushroom Fields biome holds the most brown mushrooms, but this biome can be hard to find. Mushroom Fields biomes are also home to mutated versions of cows called mooshrooms. Red mooshrooms spawn naturally and turn into brown mooshrooms when struck by lightning. When this happens, you can shear a brown mooshroom to get brown mushrooms.
If you’re on a budget (in-game, at least), caves and dark forests are your fastest options.
How to Get Sugar
To obtain sugar in Minecraft, simply collect some sugar cane and put it in a crafting grid block. Sugar cane naturally grows near the water on dirt blocks, and to find it more frequently, visit deserts and swamps.
One piece of sugar cane placed in a crafting table gives you one sugar. That’s all you need. Plant a few stalks near water if you want a renewable supply going forward.
How to Craft a Fermented Spider Eye
Once you have all three ingredients, the crafting process is straightforward.
In the first row, there should be 1 spider eye in the first box, 1 brown mushroom in the second box, and 1 sugar in the third box.
However, the recipe is actually more flexible than it looks. The crafting pattern isn’t definitive, implying that you can put the spider eye, sugar, and brown mushroom in any arrangement and still get the fermented spider eye. The only condition is that all three items must be adjacent to each other.
Steps:
- Open your crafting table (the 3×3 grid – not your inventory grid).
- Place the spider eye, brown mushroom, and sugar anywhere in the grid, as long as they touch.
- Grab the fermented spider eye from the output slot.
That’s it. No furnace. No smelting. No drama.
What Can You Do With a Fermented Spider Eye?
This is where things get interesting. Fermented spider eyes can be used to brew potions with negative effects, as well as potions of Invisibility.
You’ll need a Brewing Stand to use it. To craft a Brewing Stand, open the crafting menu and combine a Blaze Rod with three stone of any kind. Once you’ve crafted a Brewing Stand, you’ll need some Blaze Powder for fuel.
Here are the four potions you can craft using a fermented spider eye:
1. Potion of Weakness
Just combine a regular Water Bottle with a Fermented Spider Eye in the brewing stand. This creates a Potion of Weakness (1:30), which reduces melee damage dealt by the target. You can extend its duration to 4:00 with Redstone Dust.
This potion also serves a very specific and important purpose beyond combat. Curing zombie villagers requires combining the Potion of Weakness with a golden apple. If you’re trying to rebuild a village or get discounted trades, this potion is essential.
2. Potion of Harming
A Potion of Harming enacts instant damage, making it super effective during player-vs-player encounters. Create this potion with one fermented spider eye and a Potion of Poison or a Potion of Healing.
If you use a Potion of Healing II, you will create a Potion of Harming II, which deals a massive 6 hearts of instant damage.
One important note: keep these potions away from undead mobs, as they will be healed rather than hurt by them.
3. Potion of Slowness
To make a Potion of Slowness, players should combine a Fermented Spider Eye with a Potion of Swiftness or a Potion of Leaping.
The base Potion of Slowness (1:30) reduces speed by 15%. You can enhance it with Redstone to make it last for 4:00, or with Glowstone to create a Potion of Slowness IV (0:20), which reduces speed by a crippling 60%.
Throw it at fleeing enemies or use it to buy yourself time. Either way, it works.
4. Potion of Invisibility
The Potion of Invisibility does just as the name implies, making the player invisible for a period of time. Knocking one of these back will give the player 3 minutes of invisibility (8 minutes with the advanced version). To make a Potion of Invisibility, players need to combine a Fermented Spider Eye and a Potion of Night Vision.
As the name suggests, drinking this potion makes you invisible, except for your armor and anything you are holding.
So if you want to truly disappear, drop the gear before you sip.
Turning Potions Into Splash Potions
These basic potions only apply to those who drink them. If you want to throw these potions at targets, combine them with gunpowder to create a splash potion.
This is especially useful with the Potion of Weakness – you can’t exactly ask a zombie villager to drink something nicely.
Can You Find Fermented Spider Eyes Without Crafting?
Technically, yes – but it’s not worth relying on. Wandering traders occasionally purchase a fermented spider eye for 3 emeralds. That means you’re selling to them, not buying. Finding them in loot chests is also rare. Crafting is by far the fastest and most reliable method.
Common Mistakes to Avoid
A few things trip people up regularly:
- Using a red mushroom instead of brown. The recipe won’t work. Brown only.
- Using the 2×2 inventory grid. You need the full 3×3 crafting table.
- Skipping the Brewing Stand fuel. You need Blaze Powder in the fuel slot before anything brews.
- Expecting it to work on all potions. The fermented spider eye only works with specific base potions. Adding it to the wrong one won’t give you anything useful.
Quick Farming Tips
If you plan to brew potions regularly, set up small farms:
- Spider eye farm: Build a mob trap near a spider spawner for a steady supply.
- Sugar cane farm: Plant rows of sugar cane next to a water channel. It grows automatically.
- Mushroom farm: Create a dark room with mycelium blocks or low light to grow brown mushrooms consistently.
Locate a spider spawner inside a cave and build a simple water-flow room that directs mobs into a kill chamber. This setup gives you spider eyes, string, and XP in one place.
Final Thoughts
The fermented spider eye isn’t the flashiest item in Minecraft, but it unlocks a whole category of potions that most casual players never use. Weakness potions cure villagers. Harming potions wreck enemies. Slowness potions control mob movement. Invisibility potions let you walk through danger undetected.
Three simple ingredients. Four powerful potions. That’s a pretty solid return on a spider you had to smack.
Now go get those spider eyes – carefully.
