Elasticsearch analyzer ignored from index settings and only working when specified directly in query

I'm trying to change the haystack default settings to something very simple:

'settings': {
"analyzer": "spanish"
}

It looks right after rebuilding the index:

$ curl -XGET 'http://localhost:9200/haystack/_settings?pretty=true'
{
"haystack" : {
"settings" : {
"index.analyzer" : "spanish",
"index.number_of_shards" : "5",
"index.number_of_replicas" : "1",
"index.version.created" : "191199"
}
}

But when testing it with some stop words it won't work as expected, it
should filter out "esto" and "que" and instead it's filtering "is" and "a"
from the English stop words:

$ curl -XGET 'localhost:9200/haystack/_analyze?text=esto+is+a+test+que&pretty=true'
{
"tokens" : [ {
"token" : "esto",
"start_offset" : 0,
"end_offset" : 4,
"type" : "",
"position" : 1
}, {
"token" : "test",
"start_offset" : 10,
"end_offset" : 14,
"type" : "",
"position" : 4
}, {
"token" : "que",
"start_offset" : 15,
"end_offset" : 18,
"type" : "",
"position" : 5
} ]

And only when I specify the analyzer in the query it works:

$ curl -XGET 'localhost:9200/haystack/_analyze?text=esto+is+a+test+que&analyzer=spanish&pretty=true'
{
"tokens" : [ {
"token" : "is",
"start_offset" : 5,
"end_offset" : 7,
"type" : "",
"position" : 2
}, {
"token" : "test",
"start_offset" : 10,
"end_offset" : 14,
"type" : "",
"position" : 4
} ]

Any idea of what am I doing wrong?

Thanks.

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