I was reading in the Youcat that
Communion only under the species of bread is also a full communion with Christ
I was always under the impression that both the bread and the wine when consecrated were both the Body Blood Soul and Divinity of Jesus, therefore it was valid and acceptable to receive Our Lord one way or the other or both.
My gluten intolerant mother-in-law told me this so I'm not entirely sure if it's just true or not. I for sure that Christ is fully present in both, but I don't know if it is valid or acceptable to only receive Him in the wine.
The passage in the Youcat may have been in reference to bringing Communion to the sick, so in that case, it's not normal for an Extraordinary Minister to carry around a chalice to bring to shut-ins.