It sounds like you have some good facts to work with. I would talk with an attorney who practices in the County where this occurred immediately. You will want to make sure you enter a plea of not guilty by signing the back of your summons/ticket and this way the Court will schedule a hearing for you. On the date of the hearing your attorney may be able to work something out with the officer prior to any hearing taking place. Talk with an attorney and make sure you understand all your options.
Although you do have an explanation as to why you were holding the container, you did still technically "possess" the alcohol under the statute. So, while you could take it to a hearing, I think the preferred course of action would be to try to resolve the matter prior to the hearing by explaining the situation again to the officer and definitely present confirmation of your military commitment. Even if the charges cannot be dropped initially, many jurisdictions approve an alternative adjudication program, where you would complete an alcohol course and/or community service, for example, in exchange for dismissal or reduction of the charges. Be aware of the license suspension issues as well.
This is a response to a general question and is not legal advice and does not constitute legal representation. You should contact an experienced DUI attorney in your area. Thanks.