diff --git a/NLP/Stemmer.hs b/NLP/Stemmer.hs
--- a/NLP/Stemmer.hs
+++ b/NLP/Stemmer.hs
@@ -1,78 +1,26 @@
-{-# OPTIONS  -XEmptyDataDecls #-}
-{-# LANGUAGE ForeignFunctionInterface #-}
 
 -- | Haskell bindings for the Snowball stemming library
-module NLP.Stemmer ( new
-                   , delete
-                   , stem
-                   , unsafeStem
-                   , Algorithm(..)
-                   , Stemmer
-                   ) where
-
-import Data.Char        (toLower)
-import Foreign          (unsafePerformIO)
-import Foreign.C        (CString, CInt, peekCStringLen, newCString)
-import Foreign.Ptr      (Ptr)
-
-data StemmerStruct
-
--- | Pointer to a stemmer instance
-type Stemmer = Ptr StemmerStruct
-
--- | Algorithms to create a stemmer instance for
-data Algorithm = Danish
-               | Dutch
-               | English
-               | Finnish
-               | French
-               | German
-               | Hungarian
-               | Italian
-               | Norwegian
-               | Portuguese
-               | Romanian
-               | Russian
-               | Spanish
-               | Swedish
-               | Turkish
-               | Porter
-               deriving Show
-
-foreign import ccall "libstemmer.h sb_stemmer_new"    sb_stemmer_new    :: CString -> CString -> IO Stemmer
-foreign import ccall "libstemmer.h sb_stemmer_delete" sb_stemmer_delete :: Stemmer -> IO ()
-foreign import ccall "libstemmer.h sb_stemmer_stem"   sb_stemmer_stem   :: Stemmer -> CString -> CInt -> IO (CString)
-foreign import ccall "libstemmer.h sb_stemmer_length" sb_stemmer_length :: Stemmer -> IO CInt
-
--- | Create a new stemmer instance.  When you're done using the stemmer, you should 'delete' it 
-new :: Algorithm -> IO Stemmer
-new algorithm = do
-    algorithm' <- algorithmCString algorithm
-    encoding   <- utf8
-    sb_stemmer_new algorithm' encoding
-
--- | Delete a stemmer instance.  Don't use it after deleting.
-delete :: Stemmer -> IO ()
-delete = sb_stemmer_delete
-
--- | Stem a word using the stemmer instance.
-stem :: Stemmer -> String -> IO String
-stem stemmer word = do
-    word'  <- newCString word
-    strPtr <- sb_stemmer_stem   stemmer word' (fromIntegral $ length word)
-    strLen <- sb_stemmer_length stemmer
-    peekCStringLen (strPtr, fromIntegral strLen)
+-- A 'pure' stemming interface. Strings should use UTF-8 encoding. 
+module NLP.Stemmer ( 
+    -- * Stemming algorithms
+      Algorithm(..)
+    -- * Stemming functions
+    , stem
+    , stemWords
+    ) where
 
-{-# NOINLINE unsafeStem #-}
--- | Unsafe stemming, use with care.
-unsafeStem :: Stemmer -> String -> String
-unsafeStem s = unsafePerformIO . stem s
+import           NLP.Stemmer.C (Algorithm)
+import qualified NLP.Stemmer.C as C
+import           Foreign       (unsafePerformIO)
 
------------------------------------------------------------
+-- | Stem a word
+stem :: Algorithm -> String -> String
+stem algorithm input = withStemmer algorithm (\stemmer -> C.stem stemmer input)
 
-utf8 :: IO CString
-utf8 = newCString "UTF_8"
+-- | Stem a list of words, more efficient than @map 'stem'@
+stemWords :: Algorithm -> [String] -> [String]
+stemWords algorithm input = withStemmer algorithm (\stemmer -> mapM (C.stem stemmer) input)
 
-algorithmCString :: Algorithm -> IO CString
-algorithmCString = newCString . firstLower . show
-    where firstLower (first:rest) = (toLower first) : rest 
+{-# NOINLINE withStemmer #-}
+withStemmer :: Algorithm -> (C.Stemmer -> IO a) -> a
+withStemmer algorithm action = unsafePerformIO $ C.withStemmer algorithm action
diff --git a/NLP/Stemmer/C.hs b/NLP/Stemmer/C.hs
new file mode 100644
--- /dev/null
+++ b/NLP/Stemmer/C.hs
@@ -0,0 +1,91 @@
+{-# OPTIONS  -XEmptyDataDecls #-}
+{-# LANGUAGE ForeignFunctionInterface #-}
+
+-- | Haskell bindings for the Snowball stemming library.
+-- This module contains all the low-level functions and are more or less direct
+-- translations of the foreign function calls.  The 'stem' function expects
+-- strings to use UTF-8 encoding.
+module NLP.Stemmer.C (
+    -- * Types
+      Algorithm(..)
+    , Stemmer
+    -- * Low level functions
+    , new
+    , delete
+    , stem
+    -- * Wrapper
+    , withStemmer
+    ) where
+
+import Data.Char        (toLower)
+import Foreign.C        (CString, CInt, peekCStringLen, newCString)
+import Foreign.Ptr      (Ptr)
+
+data StemmerStruct
+
+-- | Pointer to a stemmer instance
+type Stemmer = Ptr StemmerStruct
+
+-- | Available algorithms.  For English, 'English' is recommended over 'Porter'.
+data Algorithm = Danish
+               | Dutch
+               | English
+               | Finnish
+               | French
+               | German
+               | Hungarian
+               | Italian
+               | Norwegian
+               | Portuguese
+               | Romanian
+               | Russian
+               | Spanish
+               | Swedish
+               | Turkish
+               | Porter
+               deriving Show
+
+foreign import ccall "libstemmer.h sb_stemmer_new"    sb_stemmer_new    :: CString -> CString -> IO Stemmer
+foreign import ccall "libstemmer.h sb_stemmer_delete" sb_stemmer_delete :: Stemmer -> IO ()
+foreign import ccall "libstemmer.h sb_stemmer_stem"   sb_stemmer_stem   :: Stemmer -> CString -> CInt -> IO (CString)
+foreign import ccall "libstemmer.h sb_stemmer_length" sb_stemmer_length :: Stemmer -> IO CInt
+
+-- | Create a new stemmer instance.  When you're done using the stemmer, you
+-- should 'delete' it, freeing the memory.
+new :: Algorithm -> IO Stemmer
+new algorithm = do
+    algorithm' <- algorithmCString algorithm
+    encoding   <- utf8
+    sb_stemmer_new algorithm' encoding
+
+-- | Delete a stemmer instance.  Don't use it after deleting.
+delete :: Stemmer -> IO ()
+delete = sb_stemmer_delete
+
+-- | Stem a word using the stemmer instance.
+stem :: Stemmer -> String -> IO String
+stem stemmer word = do
+    word'  <- newCString word
+    strPtr <- sb_stemmer_stem   stemmer word' (fromIntegral $ length word)
+    strLen <- sb_stemmer_length stemmer
+    peekCStringLen (strPtr, fromIntegral strLen)
+
+-----------------------------------------------------------
+
+-- | Perform stemming using a wrapper handling the low-level creation and
+-- deletion of the stemmer instance.
+withStemmer :: Algorithm -> (Stemmer -> IO a) -> IO a
+withStemmer algorithm action = do
+    stemmer <- new algorithm
+    result  <- action stemmer
+    delete stemmer
+    return result
+
+-----------------------------------------------------------
+
+utf8 :: IO CString
+utf8 = newCString "UTF_8"
+
+algorithmCString :: Algorithm -> IO CString
+algorithmCString = newCString . firstLower . show
+    where firstLower (first:rest) = (toLower first) : rest 
diff --git a/stemmer.cabal b/stemmer.cabal
--- a/stemmer.cabal
+++ b/stemmer.cabal
@@ -1,5 +1,5 @@
 Name:            stemmer
-Version:         0.1
+Version:         0.2
 Synopsis:        Haskell bindings to the Snowball stemming library.
 Description:     Haskell bindings to the Snowball stemming library.
 Category:        Natural Language Processing, Text
@@ -8,7 +8,8 @@
 Copyright:       (c) 2008 Tupil
 Author:          Tupil
 Maintainer:      Eelco Lempsink <eml+stemmer@tupil.com>
-Exposed-Modules: NLP.Stemmer
+Homepage:        http://blog.tupil.com/tag/stemmer
+Exposed-Modules: NLP.Stemmer, NLP.Stemmer.C
 Build-Type:      Simple
 Build-Depends:   base
 Extensions:      ForeignFunctionInterface