I am going to some festivals this year but I still struggle to find the most convenient method to cool my beer there.
I already tried bringing a cool box but it was warm after a few hours the first day in. Digging a hole wasn't such a nice idea either.
What is your best method or should I just embrace warm beer?
A high-end cooler packed with ice can stay cold for five or six days. High-end coolers can get somewhat expensive, they aren't necessary for most people. First thing I would do is get a cheap cooler, not the styrofoam cooler that you might get from a gas-station but, an double-wall insulated plastic one. The way that you pack it will make a big difference in how long it stays cold.
If you can, bring the cooler down to temperature by sticking some ice in it a day before your trip. For the trip, use the biggest ice that you can, small ice melts faster. You can fill big plastic juice bottles with water and freeze them. You also want to fill as much of the cooler as you can, so fill in smaller spaces with smaller ice. Put a folded-towel inside of the cooler, on top of everything else, to prevent too much cold air from escaping when you open your cooler. The towel should take up the entire surface-area of the cooler and when you grab a beer, only lift as much of the towel as necessary. Avoid opening the cooler more than you have to, so grab everyone a fresh beer at the same time. Of course, try to keep your cooler in the shade.
Without ice, you could take a note from the botijo. A botijo is a ceramic jug, called different things but, used around the world as a water jug. The ceramic is porous so it 'sweats'. And just like a with a person, when the 'sweat' evaporates it cools the container down. I wouldn't put beer in it, it'd go flat and it'd be hard to clean. But you could get a growler, keep it wet, and aim a portable fan at it. I don't know how well it'd work but, it's worth a shot. If the beer doesn't stay cold, at least the fan will cool you off.
I gave this some more thought. If money is no object, then there is an easy solution. It involves electricity but from a generator so it's a self contained unit. It will set you back about $2500, but it is a good solution.
Get yourself a Dometic 12v Cooler that will fit your corny keg.
Then bring a generator to power it all weekend. One of these Honda generators should last at least three days on a full tank
What is the best way to cool your beer on a festival without electricity?
That will depend on on several issues.
First of all some beers may be better served at warmer temperatures than other beers.
Depends on the beer really. A good rule of thumb is darker beer should be served at a warmer temperature than lighter beer.
For instance if you refrigerate all of your beers and then pull them out of the fridge and drink them instantly you will miss A LOT of the flavor complexity of pretty much every stout and porter you put to your lips.
But, if you let the dark stuff warm up for just 15 minutes before you drink it (let it sit at room temp) a bunch of new flavors will appear that you never would have noticed otherwise.
This doesn't work so well, in my experience, for lighter beers like pilsner, lager, or hefe-weisen. They really are meant to be drank cold and letting them get warm changes their flavor profile for the worse.
Obviously there will always be personal preferences but, at a minimum I encourage you to try letting your darker beers warm up just a bit and see what a positive difference it makes. - What temperature should I serve my beer?
Another possible idea is that if you are near water you can get a Floating Cooler For River or Pool. They range from 6 cans to 72 cans.
Intex Mega Chill II Inflatable Floating Cooler, 48" X 38" holds 72 cans.
Then of coarse there is the traditional cooler method. The larger the cooler and the more ice there is in it will keep your beer warmer.
There is also a Coleman Thermo-electric 12V Ice Chest which may serve your purpose. This what I when I go camping. No ice is recommended. You have to pre-cool the cooler at home and then plug it into the outlet in car or truck. keep the chest plugged into your vehicle the whole trip to your destination. One fall back to this system is that you can not leave plugged into your vehicle more than 3 hours without the car or truck running. But then you can either take an additional cooler or floater with you.
Coleman 40 Quart Power Chill Thermo-electric Cooler is what I use and it works great. Use it with darker beers and give it a try. Do not open it every 5 minutes and recharge it in the car every so often. It works like a charm.
If you are lucky there may be a cold natural spring near by to place your beer into.
As others have said, time frame is an important consideration. I've used a mix of dry ice, ice and salt before and had no problems in a standard, single walled, plastic box for half a day. A bit overkill perhaps...
