diff --git a/storage/itemgroup.lua b/storage/itemgroup.lua
index 94bc998..0f48c76 100644
--- a/storage/itemgroup.lua
+++ b/storage/itemgroup.lua
@@ -141,6 +141,10 @@ function ItemGroup:transferTo(target, itemCount)
   local transferMax = math.min(itemCount or targetCap, targetCap, self:getItemCount())
   local transfer = 0
   for _,stack in targetGroup:_iterateStacks() do
+    if transfer == transferMax then
+      break
+    end
+
     local targetCount = math.min(stack:getCount() + transferMax - transfer, stack:getMaxCount())
     for _,from in self:_iterateStacks() do
       if stack:getCount() == targetCount then