diff --git a/lib/csv.rb b/lib/csv.rb
index 9bb1830..dc431ed 100644
--- a/lib/csv.rb
+++ b/lib/csv.rb
@@ -1861,7 +1861,7 @@ def shift
               raise MalformedCSVError,
                     "Missing or stray quote in line #{lineno + 1}"
             end
-            csv.last.gsub!(@quote_char * 2, @quote_char)
+            csv.last.gsub!(@double_quote_char, @quote_char)
             in_extended_col = false
           else
             csv.last << part
@@ -1881,7 +1881,7 @@ def shift
               raise MalformedCSVError,
                     "Missing or stray quote in line #{lineno + 1}"
             end
-            csv.last.gsub!(@quote_char * 2, @quote_char)
+            csv.last.gsub!(@double_quote_char, @quote_char)
           elsif @liberal_parsing
             csv << part
           else
@@ -1999,6 +1999,7 @@ def init_separators(options)
     @col_sep    = options.delete(:col_sep).to_s.encode(@encoding)
     @row_sep    = options.delete(:row_sep)  # encode after resolving :auto
     @quote_char = options.delete(:quote_char).to_s.encode(@encoding)
+    @double_quote_char = @quote_char * 2
 
     if @quote_char.length != 1
       raise ArgumentError, ":quote_char has to be a single character String"