Keep non-stemmed tokens on Elasticsearch

I'm using a stemmer (for the Brazilian Portuguese Language) when I index documents on Elasticsearch. This is what my default analyzer looks like(nvm minor mistakes here because I've copied this by hand from my code in the server):

{
    "analysis":{
        "filter":{
            "my_asciifolding": {
                "type": "asciifolding",
                "preserve_original": true,  
            },
            "stop_pt":{
                "type": "stop",
                "ignore_case": true,
                "stopwords": "_brazilian_"
            },
            "stemmer_pt": {
                "type": "stemmer",
                "language": "brazilian"
            }
        },
        "analyzer": {
            "default": {
                "type": "custom",
                "tokenizer": "standard",
                "filter": [
                    "lowercase",
                    "my_asciifolding",
                    "stop_pt",
                    "stemmer_pt"
                ]
            }
        }
    }
}

I haven't really touched my type mappings (apart from a few numeric fields I've declared "type":"long") so I expect most fields to be using this default analyzer I've specified above.

This works as expected, but the thing is that some users are frustrated because (since tokens are being stemmed), the query "vulnerabilities" and the query "vulnerable" return the same results, which is misleading because they expect the results having an exact match to be ranked first.

Whats is the default way (if any) to do this in elasticsearch? (maybe keep the unstemmed tokens in the index as well as the stemmed tokens?) I'm using version 1.5.1.

Solution

I ended up using "fields" field to index my attributes in different ways. Not sure whether this is optimal but this is the way I'm handling it right now:

Add another analyzer (I called it "no_stem_analyzer") with all filters that the "default" analyzer has, minus "stemmer".

For each attribute I want to keep both non stemmed and stemmed variants, I did this (example for field "DESCRIPTION"):

"mappings":{
  "_default_":{
    "properties":{
      "DESCRIPTION":{
        "type"=>"string",
        "fields":{
          "no_stem":{
            "type":"string",
            "index":"analyzed",
            "analyzer":"no_stem_analyzer"
          },
          "stemmed":{
            "type":"string",
            "index":"analyzed",
            "analyzer":"default"                
          }
        }
      } 
    },//.. other attributes here
  }
}

At search time (using query_string_query) I must also indicate (using field "fields") that I want to search all sub-fields (e.g. "DESCRIPTION.*")

I also based my approach upon [this answer].(elasticsearch customize score for synonyms/stemming)