diff --git a/lib/ulid/constants.rb b/lib/ulid/constants.rb
index 2a8eed5..cbd209a 100644
--- a/lib/ulid/constants.rb
+++ b/lib/ulid/constants.rb
@@ -12,10 +12,10 @@ module Constants
 
     # Crockford's Base32. Alphabet portion is missing I, L, O, and U.
     ENCODING = "0123456789ABCDEFGHJKMNPQRSTVWXYZ"
-
+    ENCODING_LIST = ENCODING.split('')
     # Byte to index table for O(1) lookups when unmarshaling.
     # We rely on nil as sentinel value for invalid indexes.
-    B32REF = Hash[ ENCODING.split('').each_with_index.to_a ]
+    B32REF = Hash[ ENCODING_LIST.each_with_index.to_a ]
   end
 end
 
diff --git a/lib/ulid/generate.rb b/lib/ulid/generate.rb
index 17a715e..48c1a87 100644
--- a/lib/ulid/generate.rb
+++ b/lib/ulid/generate.rb
@@ -24,34 +24,34 @@ def encode32
       # decoded into the original bytes.
 
       # 10 byte timestamp
-      output << ENCODING[(id[0]&224)>>5]
-      output << ENCODING[id[0]&31]
-      output << ENCODING[(id[1]&248)>>3]
-      output << ENCODING[((id[1]&7)<<2)|((id[2]&192)>>6)]
-      output << ENCODING[(id[2]&62)>>1]
-      output << ENCODING[((id[2]&1)<<4)|((id[3]&240)>>4)]
-      output << ENCODING[((id[3]&15)<<1)|((id[4]&128)>>7)]
-      output << ENCODING[(id[4]&124)>>2]
-      output << ENCODING[((id[4]&3)<<3)|((id[5]&224)>>5)]
-      output << ENCODING[id[5]&31]
+      output << ENCODING_LIST[(id[0]&224)>>5]
+      output << ENCODING_LIST[id[0]&31]
+      output << ENCODING_LIST[(id[1]&248)>>3]
+      output << ENCODING_LIST[((id[1]&7)<<2)|((id[2]&192)>>6)]
+      output << ENCODING_LIST[(id[2]&62)>>1]
+      output << ENCODING_LIST[((id[2]&1)<<4)|((id[3]&240)>>4)]
+      output << ENCODING_LIST[((id[3]&15)<<1)|((id[4]&128)>>7)]
+      output << ENCODING_LIST[(id[4]&124)>>2]
+      output << ENCODING_LIST[((id[4]&3)<<3)|((id[5]&224)>>5)]
+      output << ENCODING_LIST[id[5]&31]
 
       # 16 bytes of entropy
-      output << ENCODING[(id[6]&248)>>3]
-      output << ENCODING[((id[6]&7)<<2)|((id[7]&192)>>6)]
-      output << ENCODING[(id[7]&62)>>1]
-      output << ENCODING[((id[7]&1)<<4)|((id[8]&240)>>4)]
-      output << ENCODING[((id[8]&15)<<1)|((id[9]&128)>>7)]
-      output << ENCODING[(id[9]&124)>>2]
-      output << ENCODING[((id[9]&3)<<3)|((id[10]&224)>>5)]
-      output << ENCODING[id[10]&31]
-      output << ENCODING[(id[11]&248)>>3]
-      output << ENCODING[((id[11]&7)<<2)|((id[12]&192)>>6)]
-      output << ENCODING[(id[12]&62)>>1]
-      output << ENCODING[((id[12]&1)<<4)|((id[13]&240)>>4)]
-      output << ENCODING[((id[13]&15)<<1)|((id[14]&128)>>7)]
-      output << ENCODING[(id[14]&124)>>2]
-      output << ENCODING[((id[14]&3)<<3)|((id[15]&224)>>5)]
-      output << ENCODING[id[15]&31]
+      output << ENCODING_LIST[(id[6]&248)>>3]
+      output << ENCODING_LIST[((id[6]&7)<<2)|((id[7]&192)>>6)]
+      output << ENCODING_LIST[(id[7]&62)>>1]
+      output << ENCODING_LIST[((id[7]&1)<<4)|((id[8]&240)>>4)]
+      output << ENCODING_LIST[((id[8]&15)<<1)|((id[9]&128)>>7)]
+      output << ENCODING_LIST[(id[9]&124)>>2]
+      output << ENCODING_LIST[((id[9]&3)<<3)|((id[10]&224)>>5)]
+      output << ENCODING_LIST[id[10]&31]
+      output << ENCODING_LIST[(id[11]&248)>>3]
+      output << ENCODING_LIST[((id[11]&7)<<2)|((id[12]&192)>>6)]
+      output << ENCODING_LIST[(id[12]&62)>>1]
+      output << ENCODING_LIST[((id[12]&1)<<4)|((id[13]&240)>>4)]
+      output << ENCODING_LIST[((id[13]&15)<<1)|((id[14]&128)>>7)]
+      output << ENCODING_LIST[(id[14]&124)>>2]
+      output << ENCODING_LIST[((id[14]&3)<<3)|((id[15]&224)>>5)]
+      output << ENCODING_LIST[id[15]&31]
 
       output
     end