Get struct Tag with reflection - Error: type reflect.Value has no field or method Tag

Let's say we have this PoC:

package main

import (
        "fmt"
        "reflect"
        "strings"
)

type MyStruct struct {
        Str string `gorm:"size:10" json:"string"`
}

func main() {
        aStruct := MyStruct{"Hello"}

        s := reflect.ValueOf(&aStruct).Elem()
        if s.Kind() == reflect.Struct {
                for i := 0; i < s.NumField(); i++ {
                        field := s.Field(i)
                        if field.IsValid() {
                                if field.CanSet() {
                                        fmt.Printf("%T\n", field)  // reflect.Value, need reflect.StructField
                                        gormTag := field.Tag.Get("gorm")  // Compile ERROR HERE
                                        gormSize := strings.Split(gormTag, "size:")[1]
                                        fmt.Println(gormSize)
                                }
                        }
                }
        }
}

The error is:

go run test1.go 
# command-line-arguments
./test1.go:22:22: field.Tag undefined (type reflect.Value has no field or method Tag)

Tested with go 1.14.6 and go 1.15.2.

In my understanding I need to cast (or get from) reflect.Value to reflect.StructField Any ideas how to do that?