3 or 5 gallon Mash Lauter Tun?

I just ordered a mini-mash kit from AHS that comes with 1.75 lbs base grains and 1.75 lbs of steeping grains. I plan on building a mash lauter tun from a round cooler and wasn't sure if a 5 gallon one would be too big for partial mash and if i was better off making one out of a 3 gallon cooler.

I like the idea of a 5 gallon because i can move up to all grain in the future. Any thoughts/input would be much appreciated.

Well you dont really need to have a mash tun to do mini-mashes, you could just use your boil kettle. But if you wanted to go ahead and build a mash tun i would have to say bigger is better. I would go for the 5 gallon cooler so then in the future you could fit 11-12 lbs of grains in it. You would max out a 3 gallon cooler quickly.

Heres a link showing a great way to partial mash without a mash tun: https://www.homebrewtalk.com/f39/easy-partial-mash-brewing-pics-75231/

Chromados

Thanks for the response. I did read through that link which is extremly helpful and my concern was maintaining temperture. I figured it would be easier to do so in a cooler and also start to get me used to procedures for all grain after the winter.

I started out with a 5 gal cooler, false bottom etc... but would really recommend something in the 7 - 10 gallon range. Here's a great post about different size mash tuns. As for maintaining temps. I injected spray foam into the lid and with a 5 gal. cooler, the head space is very low so I had no temp fluctuation for my mash. Oh, and pre-heating your MLT is a good idea if you're strike water is at or near your mash temp.