Cannot access jQuery private object methods

I have a function like this:

var eatLunch = (function () {
    var sandwiches = [$("#sand1"), $("#sand2")];

    return function (eaten) {
        for (var i = 0, len = eaten.length; i < len; i++) {
            sandwiches[i].attr("class", "eaten-by " + eaten[i].by)
        }
    };
}());

eatLunch([
    {
        result: "good",
        by: "Adam"
    },
    {
        result: "meh",
        by: "Adam"
    }
]);

The goal is to cache the dom # sand1 and # sand2 elements in close to reduce the amount of interference this function should perform. Without closing, elements should be assigned to variables every time I call a function.

However, the attr method does not work. Upon further inspection, sandwiches [i] are determined and it has the attr method. The function does not throw an error, it just continues the loop, but the dom elements are not updated.

If I move the sandwiches to a local volume, it works fine, but it's more expensive. See below:

var eatLunch = function (eaten) {
    var sandwiches = [$("sand1"), $("sand2")];

    for (var i = 0, len = eaten.length; i < len; i++) {
        sandwiches[i].attr("class", "eaten-by " + eaten[i].by)
    }
};

eatLunch([
    {
        result: "good",
        by: "Adam"
    },
    {
        result: "meh",
        by: "Adam"
    }
]);

What's going on here?