diff --git a/coal-crafter.lua b/coal-crafter.lua
index 3243fa6..c80cb98 100644
--- a/coal-crafter.lua
+++ b/coal-crafter.lua
@@ -1,9 +1,26 @@
 local turtleUtils = require('libs/turtle-utils')
 
+local NB_NEEDED_COAL = 256
 local WAIT_INVENTORY_TIME = 3
-local IDLE_TIME = 10
+local IDLE_TIME = 30
+local IDLE_TIME_ENOUGH_COAL = 120
 local MIN_ESSENCE_NEEDED = 8
 local COAL_ESSENCE_NAME = 'mysticalagriculture:coal_essence'
+local COAL_NAME = 'minecraft:coal'
+
+local function waitForNotEnoughCoal(inventory)
+  while true do
+    for slot, item in pairs(inventory.list()) do
+      local enoughCoal = item.name == COAL_NAME and item.count >= NB_NEEDED_COAL
+
+      if not enoughCoal then
+        return
+      end
+    end
+
+    os.sleep(IDLE_TIME_ENOUGH_COAL)
+  end
+end
 
 -- the slot of the coal essence is returned
 local function waitForCoalEssence(inventory)
@@ -89,6 +106,7 @@ local function main()
     storageInventory = turtleUtils.waitForInventory('back', WAIT_INVENTORY_TIME)
     bufferInventory = turtleUtils.waitForInventory('front', WAIT_INVENTORY_TIME)
 
+    waitForNotEnoughCoal(storageInventory)
     local coalEssenceSlot = waitForCoalEssence(storageInventory)
     local pushOk = storageInventory.pushItems(peripheral.getName(bufferInventory), coalEssenceSlot, MIN_ESSENCE_NEEDED)