diff --git a/lib/jekyll/filters.rb b/lib/jekyll/filters.rb
index 2e4a1174..fc0907a9 100644
--- a/lib/jekyll/filters.rb
+++ b/lib/jekyll/filters.rb
@@ -328,14 +328,23 @@ module Jekyll
 
     def as_liquid(item)
       case item
-      when String, Numeric, true, false, nil
-        item.to_liquid
       when Hash
-        Hash[item.map { |k, v| [as_liquid(k), as_liquid(v)] }]
+        pairs = item.map { |k, v| as_liquid([k, v]) }
+        Hash[pairs]
       when Array
         item.map{ |i| as_liquid(i) }
-      else
-        item.respond_to?(:to_liquid) ? as_liquid(item.to_liquid) : item
+      else # simple type
+        if item.respond_to?(:to_liquid)
+          liquidated = item.to_liquid
+          # prevent infinite recursion
+          if liquidated == item
+            item
+          else
+            as_liquid(liquidated)
+          end
+        else
+          item
+        end
       end
     end
   end