diff --git a/src/inventory.cpp b/src/inventory.cpp
index 86e00877c..ccd55a79f 100644
--- a/src/inventory.cpp
+++ b/src/inventory.cpp
@@ -90,6 +90,19 @@ InventoryItem* InventoryItem::deSerialize(std::istream &is)
 	}
 }
 
+/*
+	MaterialItem
+*/
+
+InventoryItem *MaterialItem::createCookResult()
+{
+	if(m_content == CONTENT_TREE)
+	{
+		return new CraftItem("lump_of_coal", 1);
+	}
+	return NULL;
+}
+
 /*
 	MapBlockObjectItem
 */
@@ -313,6 +326,11 @@ u32 InventoryList::getUsedSlots()
 	return num;
 }
 
+u32 InventoryList::getFreeSlots()
+{
+	return getSize() - getUsedSlots();
+}
+
 InventoryItem * InventoryList::getItem(u32 i)
 {
 	if(i > m_items.size() - 1)
diff --git a/src/inventory.h b/src/inventory.h
index 0cbd97abc..d110f92c0 100644
--- a/src/inventory.h
+++ b/src/inventory.h
@@ -72,6 +72,7 @@ public:
 	{
 		m_count = count;
 	}
+	// This should return something else for stackable items
 	virtual u16 freeSpace()
 	{
 		return 0;
@@ -87,6 +88,14 @@ public:
 		m_count -= count;
 	}
 
+	/*
+		Other properties
+	*/
+	// Time of cooking
+	virtual float getCookTime(){return 3.0;}
+	// Result of cooking
+	virtual InventoryItem *createCookResult(){return NULL;}
+
 protected:
 	u16 m_count;
 };
@@ -148,6 +157,10 @@ public:
 			return 0;
 		return QUANTITY_ITEM_MAX_COUNT - m_count;
 	}
+	/*
+		Other properties
+	*/
+	InventoryItem *createCookResult();
 	/*
 		Special methods
 	*/
@@ -428,6 +441,7 @@ public:
 	u32 getSize();
 	// Count used slots
 	u32 getUsedSlots();
+	u32 getFreeSlots();
 	
 	// Get pointer to item
 	InventoryItem * getItem(u32 i);
diff --git a/src/nodemetadata.cpp b/src/nodemetadata.cpp
index 21f55a0ca..21b4ed01d 100644
--- a/src/nodemetadata.cpp
+++ b/src/nodemetadata.cpp
@@ -177,7 +177,7 @@ FurnaceNodeMetadata::FurnaceNodeMetadata()
 	m_inventory = new Inventory();
 	m_inventory->addList("fuel", 1);
 	m_inventory->addList("src", 1);
-	m_inventory->addList("dst", 1);
+	m_inventory->addList("dst", 4);
 
 	m_step_accumulator = 0;
 	m_fuel_totaltime = 0;
@@ -202,12 +202,15 @@ NodeMetadata* FurnaceNodeMetadata::clone()
 NodeMetadata* FurnaceNodeMetadata::create(std::istream &is)
 {
 	FurnaceNodeMetadata *d = new FurnaceNodeMetadata();
+
 	d->m_inventory->deSerialize(is);
+
 	int temp;
 	is>>temp;
 	d->m_fuel_totaltime = (float)temp/10;
 	is>>temp;
 	d->m_fuel_time = (float)temp/10;
+
 	return d;
 }
 void FurnaceNodeMetadata::serializeBody(std::ostream &os)
@@ -260,9 +263,10 @@ bool FurnaceNodeMetadata::step(float dtime)
 	InventoryList *src_list = m_inventory->getList("src");
 	assert(src_list);
 	InventoryItem *src_item = src_list->getItem(0);
-
-	if(ItemSpec(ITEM_MATERIAL, CONTENT_TREE).checkItem(src_item)
-			&& dst_list->itemFits(0, new CraftItem("lump_of_coal", 1)))
+	
+	// Start only if there are free slots in dst, so that it can
+	// accomodate any result item
+	if(dst_list->getFreeSlots() > 0)
 	{
 		m_src_totaltime = 3;
 	}
@@ -279,13 +283,11 @@ bool FurnaceNodeMetadata::step(float dtime)
 		m_src_time += dtime;
 		if(m_src_time >= m_src_totaltime && m_src_totaltime > 0.001)
 		{
-			if(ItemSpec(ITEM_MATERIAL, CONTENT_TREE).checkItem(src_item))
-			{
-				src_list->decrementMaterials(1);
-				dst_list->addItem(0, new CraftItem("lump_of_coal", 1));
-				m_src_time = 0;
-				m_src_totaltime = 0;
-			}
+			src_list->decrementMaterials(1);
+			InventoryItem *cookresult = src_item->createCookResult();
+			dst_list->addItem(cookresult);
+			m_src_time = 0;
+			m_src_totaltime = 0;
 		}
 		return true;
 	}
@@ -340,6 +342,10 @@ void NodeMetadataList::serialize(std::ostream &os)
 {
 	u8 buf[6];
 	
+	u16 version = 1;
+	writeU16(buf, version);
+	os.write((char*)buf, 2);
+
 	u16 count = m_data.size();
 	writeU16(buf, count);
 	os.write((char*)buf, 2);
@@ -365,6 +371,16 @@ void NodeMetadataList::deSerialize(std::istream &is)
 
 	u8 buf[6];
 	
+	is.read((char*)buf, 2);
+	u16 version = readU16(buf);
+
+	if(version > 1)
+	{
+		dstream<<__FUNCTION_NAME<<": version "<<version<<" not supported"
+				<<std::endl;
+		throw SerializationError("NodeMetadataList::deSerialize");
+	}
+	
 	is.read((char*)buf, 2);
 	u16 count = readU16(buf);