What is in your SPT-twist field?
What are you doing with this field? Aggs? Sorting? Searching?
I can totally answer to your question but I don't want to "just answer".
I prefer giving you the best practice with elasticsearch.
So if you can share a full recreation script as described in About the Elasticsearch category. It will help to better understand what you are exactly doing. Please, try to keep the example as simple as possible.
Then I'll be able to give you a real advice and not just a technical answer.