Is a 10 gallon MLT overkill?

I'm finally making the swap to all grain and I went and picked up supplies to build a MLT, I went with the 10 gallon igloo cooler. I plan on doing 5 gallon batches for now. Is 10 gallons to much heat loss? How big of a cooler do you guys use?

I think you will be fine.

I also have the ten gallon igloo but I only brew 5 gallon batches.

So far, no problems maintaining temps. I made a sort of floating insulated cover to sit on top of the grain bed but, so far, I haven't really needed it.

10 gallon is perfect for 5 gallon batches IMO. That is what I started with. Allows you to do some big beers as well.

Thanks I wasn't even really worried, but as I laid in bed last night my girlfriend looked at the cooler sitting on my dresser and said "that's bigger than your dresser". And when she said that my confidence shattered.

I use a 10 gallon MLT cooler for my 5 gallon batches. For most beers, yeah, it's overkill but I really don't notice any heat loss issues. Plus, there's plenty of room for big beers with larger grain bills.

Just make sure to put some strike water in the cooler before u add the bulk of the water. Swirl it around and let it sit for a few minutes, then either dump it out or back into the vessel ur using to heat the strike water. That'll help keep u from needing warmer water

I use a 10 gallon cooler for 5 gallon batches. I just heat my strike water a bit warmer (5-10 degrees F) than my target, and let that preheat the cooler. Once the water in the cooler is at my target temp I mash in. Have hit my temps that way so far using a strike water calculator like http://www.brewheads.com/strike.php or in whatever software you use. I have only lost about 1 degree over a 60 min mash.

I saw this method in Bobby_M's all grain primer, and it has worked well for me. http://www.suebob.com/brew/Bobby_Mallgrainprimer.pdf

I would do the 10g over the 5g. It gives you more options. Big beers and Batch Sparging Big Beers -- 2 huge pluses for me (especially batch sparging, I have no desire to fly sparge). I also like to brew 6g batches so I have 5.5 going into the keg.

EDIT: I have a 10g Orange Home Depot (I think its rubbermaid) round cooler. I am incredibly happy with it. That and my grain mill are my favorite, most rewarding pieces of home brew equipment I have.

I agree that you will not regret having the 10 gallon size. If anything you might want even a little bigger. I have the 10 gallon Rubbermaid and have made one big beer that filled it pretty high. I would not have been able to do it in anything smaller.

Ya, I went with a 7 gallon and although I have fewer problems with maintaining temp than I used to obviously it's a bit tight in there.

Personally I bought a 10 gallon Home Depot for cooler for $50ish and though man this is HUGE! And the next weekend I was at Lowes and seen they had 5 gallon Igloo coolers on clearance for $10 so I bought one of those and returned my 10 gallon cooler to Home Depot. The 5 gallon is much easier to store and I decided if I am to make a big beer and cant live with a smaller batch I will just do a partial mash, I believe for 90% of what I will make though I will be more than happy.

I am in the process of making a copper manifold for it, I am going to batch sparge but I had the copper laying around so I am going to try out my luck with a manifold rather than the braid.

I want to add though I only brew enough for me though as I am the lone drinker in the house so I am not going for quantity.

I have the 70 qt. coleman extreme, and I have done 2 5 gal batches in there so far, 1 large and 1 small grain bill, and I have lost maybe 2 deg. over an hour mash, so you will be fine with the 10 gal, and will appreciate the extra space when you want to do a big beer. +1 on the preheating though, either by shooting a little high on your strike temp and letting it drop, or I just fill mine with about 3-4 gallons of hot water straight from the tap (130ish) and let that sit for 20-30 min. while I am getting the rest of my stuff together. Beersmith will even let you put in the temp. of your pre-heated tun and account for that in strike temp. calculations.

I bought a 10 gallon Rubbermaid and am very happy with the size. I've been brewing 5 gallon batches and I notice that when preheating the cooler I don't lose temp over an hour. I also like that I have the space to up my batch size a bit if I want. I'm going to try for a 7.5 gallon batch just for kicks to see how it works out.

I started with a 5 gallon Rubbermaid I converted using instructions from the Wiki and it worked great. But, I came across a free 10 gallon Igloo and decided to convert that too. I have used the 10 gallon ever since. I don't really have any issues maintaining temperatures (even on lower gravity beers). I now use the 5 gallon as an HLT.

By the way, the 10 gallon Igloo conversion usually requires a rubber grommet for the drain hole as this hole (in my experience) is bigger than the Rubbermaid counterpart. Otherwise, the ball valve will not fit snugly and you will not be able to maintain a seal.