Hello. 

I have transferStackInSlot method and use hasRecipe for find if itemstack is present in recipe.

@Override
public ItemStack transferStackInSlot(PlayerEntity playerIn, int index) {
	ItemStack itemstack = ItemStack.EMPTY;
	Slot slot = this.inventorySlots.get(index);
	if(slot != null && slot.getHasStack()) {
		ItemStack itemstack1 = slot.getStack();
		itemstack = itemstack1.copy();
		if(index == 2) {
			if(!this.mergeItemStack(itemstack1, 3, 39, true)) {
				return ItemStack.EMPTY;
			}

			slot.onSlotChange(itemstack1, itemstack);
		} else if(index != 1 && index != 0) {
			if(this.hasRecipe(itemstack1)) {
				if(!this.mergeItemStack(itemstack1, 1, 2, false)) {
					return ItemStack.EMPTY;
				}
			} else if(this.isBucket(itemstack1)) {
				if(!this.mergeItemStack(itemstack1, 0, 1, false)) {
					return ItemStack.EMPTY;
				}
			} else if(index >= 3 && index < 30) {
				if(!this.mergeItemStack(itemstack1, 30, 39, false)) {
					return ItemStack.EMPTY;
				}
			} else if(index >= 30 && index < 39 && !this.mergeItemStack(itemstack1, 3, 30, false)) {
				return ItemStack.EMPTY;
			}
		} else if(!this.mergeItemStack(itemstack1, 3, 39, false)) {
			return ItemStack.EMPTY;
		}

		if(itemstack1.isEmpty()) {
			slot.putStack(ItemStack.EMPTY);
		} else {
			slot.onSlotChanged();
		}

		if(itemstack1.getCount() == itemstack.getCount()) {
			return ItemStack.EMPTY;
		}

		slot.onTake(playerIn, itemstack1);
	}

	return itemstack;
}	

protected boolean hasRecipe(ItemStack stack) {
	return this.world.getRecipeManager().getRecipe(MaltingRecipe.RECIPE_TYPE, new Inventory(stack), world).isPresent();
}

But hasRecipe return false for all itemstack, but i have recipe who works.

Recipe:

{
	"type": "realistic_beer_brewing:malting",
  	"ingredient": {
    	"item": "realistic_beer_brewing:barley"
  	},
  	"result": {
        "item": "realistic_beer_brewing:barley_seed"
    },
  	"process_time": 200
}

Recipe in this tile entity works.

Nobody knows?

On 5/19/2020 at 9:51 AM, grossik said:

return this.world.getRecipeManager().getRecipe(MaltingRecipe.RECIPE_TYPE, new Inventory(stack), world).isPresent();

If it returns false for all item stacks, then either:

1. Your MaltingRecipe recipe list is empty
2. You're using the recipe manager incorrectly