Elasticsearch is a Fulltext search solution not a K/V Database.
EDIT: Color me surprised. I didn't see it mentioned at all in the ElasticSearch docs or in their Github repo, but apparently this is a fairly popular thing to do.
"Elastic search as a database?" http://stackoverflow.com/questions/6636508/elastic-search-as...
"ElasticSearch, datastore for user and social data?" http://stackoverflow.com/questions/8190288/elasticsearch-dat...
"Elasticsearch and NoSql database" http://stackoverflow.com/questions/8026880/elasticsearch-and...