For those following the GIRM as approved for the U.S. I was not aware of this. I didn’t realize there were occasions where the minister can choose. Can you help/clarify? Thanks.
In addition to what Benedictgal already posted, there are some practical reasons for denying Communion in the hand in favor of Communion on the tongue.
Here are a few examples:
If a person has unwashed hands. I don’t mean “stained.” I mean if someone is being disrespectful by knowingly attempting to receive with unwashed hands, such as a young person who’s been “playing in the mud” or some such. This is different from someone who has “stained” hands because of work or a hobby, even though they might be stained, they were still cleaned.
When I say Mass at the high school, I don’t allow Communion in the hand to students who have used their hands as notebooks. I’m not going to place the Body of Christ onto a palm that has a drawing of a heart with the words “Suzy luvz Eddie” and “Jackies new cell 212-555-1212”. And yes, that does happen.
And yes, the (then-called) Congregation for Divine Worship addressed this issue of clean hands in 1985.
Someone who is obviously not about to receive in the way that the rubrics describe. Examples: a woman who is also carrying a purse in one hand, or a parent carrying a child. Not only are they unable (or sometimes unwilling) to receive in the way the Church describes, but the danger of the Host falling is obvious. I’ve also had people try to receive in the hand while holding a cell phone. Note the word “try.”
Another reason would be the rare times when I have no choice but to break apart the Hosts because there aren’t enough. In that case, the danger of crumbs falling is very real and I won’t give on the hand–only on the tongue.
The minister cannot choose the manner in which the communicant receives. However the minister can (and sometimes even must) refuse on an individual basis to distribute on the hand IF the communicant doesn’t intend to receive with due reverence, according to the rubrics, or if there’s some danger of outright profanation (such as walking away with the Host).