Problem with the UTF-8 encoding

I got this testcase:
```ruby
require 'beefcake'

class StrTest
  include Beefcake::Message
  required :name, :string, 1
  
end

string_test = StrTest.new

string_test.name = 'Cool name!'

puts "Stored Encoding: #{string_test.name.encoding}"

new_string_test = StrTest.decode string_test.encode

puts "Got Encoding: #{new_string_test.name.encoding}"
```
This prints out:
Stored Encoding: UTF-8
Got Encoding: ASCII-8BIT
On Ruby 2.1.2 also tried jRuby 1.7.13 .

How do I make it spit out UTF-8 strings with correct encoding?