diff --git a/lib/linguist/blob_helper.rb b/lib/linguist/blob_helper.rb
index a942b205..08e88581 100644
--- a/lib/linguist/blob_helper.rb
+++ b/lib/linguist/blob_helper.rb
@@ -2,6 +2,7 @@ require 'linguist/language'
 require 'linguist/mime'
 require 'linguist/pathname'
 
+require 'charlock_holmes'
 require 'escape_utils'
 require 'pygments'
 require 'yaml'
@@ -52,7 +53,7 @@ module Linguist
     #
     # Returns a content type String.
     def content_type
-      pathname.content_type
+      @content_type ||= binary? ? mime_type : "text/plain; charset=#{encoding.downcase}"
     end
 
     # Public: Get the Content-Disposition header value
@@ -71,11 +72,30 @@ module Linguist
       end
     end
 
+    def encoding
+      if hash = detect_encoding
+        hash[:encoding]
+      end
+    end
+
+    # Try to guess the encoding
+    #
+    # Returns: a Hash, with :encoding, :confidence, :type
+    #          this will return nil if an error occurred during detection or
+    #          no valid encoding could be found
+    def detect_encoding
+      @detect_encoding ||= CharlockHolmes::EncodingDetector.new.detect(data) if data
+    end
+
     # Public: Is the blob binary?
     #
     # Return true or false
     def binary?
-      pathname.binary?
+      if mime_type = Mime.lookup_mime_type_for(pathname.extname)
+        mime_type.binary?
+      else
+        detect_encoding.nil? || detect_encoding[:type] == :binary
+      end
     end
 
     # Public: Is the blob text?
@@ -529,6 +549,8 @@ module Linguist
     # Returns html String
     def colorize(options = {})
       return if !text? || large?
+      options[:options] ||= {}
+      options[:options][:encoding] ||= encoding
       lexer.highlight(data, options)
     end
 
@@ -540,7 +562,7 @@ module Linguist
     # Returns html String
     def colorize_without_wrapper(options = {})
       return if !text? || large?
-      if text = lexer.highlight(data, options)
+      if text = colorize(options)
         text[%r{<div class="highlight"><pre>(.*?)</pre>\s*</div>}m, 1]
       else
         ''
diff --git a/test/test_blob.rb b/test/test_blob.rb
index 3602a9d6..bc8a00be 100644
--- a/test/test_blob.rb
+++ b/test/test_blob.rb
@@ -38,14 +38,11 @@ class TestBlob < Test::Unit::TestCase
     assert_equal "application/octet-stream", blob("dog.o").content_type
     assert_equal "application/pdf", blob("foo.pdf").content_type
     assert_equal "image/png", blob("foo.png").content_type
-    assert_equal "text/plain; charset=utf8", blob("README").content_type
-    assert_equal "text/plain; charset=utf8", blob("foo.html").content_type
-    assert_equal "text/plain; charset=utf8", blob("foo.pl").content_type
-    assert_equal "text/plain; charset=utf8", blob("foo.py").content_type
-    assert_equal "text/plain; charset=utf8", blob("foo.rb").content_type
-    assert_equal "text/plain; charset=utf8", blob("foo.sh").content_type
-    assert_equal "text/plain; charset=utf8", blob("foo.xhtml").content_type
-    assert_equal "text/plain; charset=utf8", blob("foo.xml").content_type
+    assert_equal "text/plain; charset=iso-8859-2", blob("README").content_type
+    assert_equal "text/plain; charset=iso-8859-1", blob("script.pl").content_type
+    assert_equal "text/plain; charset=iso-8859-1", blob("script.py").content_type
+    assert_equal "text/plain; charset=iso-8859-1", blob("script.rb").content_type
+    assert_equal "text/plain; charset=iso-8859-1", blob("script.sh").content_type
   end
 
   def test_disposition
@@ -79,6 +76,13 @@ class TestBlob < Test::Unit::TestCase
     assert_equal 2, blob("foo.rb").sloc
   end
 
+  def test_encoding
+    assert_equal "ISO-8859-2", blob("README").encoding
+    assert_equal "ISO-8859-1", blob("dump.sql").encoding
+    assert_equal "UTF-8", blob("file.txt").encoding
+    assert_nil blob("dog.o").encoding
+  end
+
   def test_binary
     assert blob("git.deb").binary?
     assert blob("git.exe").binary?
@@ -86,6 +90,7 @@ class TestBlob < Test::Unit::TestCase
     assert blob("linguist.gem").binary?
     assert blob("octocat.ai").binary?
     assert blob("octocat.png").binary?
+    assert blob("zip").binary?
     assert !blob("README").binary?
     assert !blob("file.txt").binary?
     assert !blob("foo.rb").binary?
@@ -330,7 +335,6 @@ class TestBlob < Test::Unit::TestCase
     assert_equal Language['Parrot Assembly'], blob("hello.pasm").language
 
     # http://gosu-lang.org
-    assert_equal Language['Gosu'], blob("Hello.gs").language
     assert_equal Language['Gosu'], blob("Hello.gsx").language
     assert_equal Language['Gosu'], blob("hello.gsp").language
     assert_equal Language['Gosu'], blob("Hello.gst").language