thickness of mash?

After taking 5 years off, I've pulled out all my equipment and have jumped back in with both feet. In the last 3 weeks, I've brewed and kegged 20 gallons (in a 10-gallon system). My question involves mash consistency.

I mash in a 10-gallon Gott cooler. I don't like to measure water for my single-infusion mashes, as I am usually struggling with water temperature variations, etc. I've always just gone by feel. I've always been happy with the results, but I wonder if I could be doing better. As a side note, I've not taken gravity readings in 15 years and probably don't plan to start.

I'm wondering if someone who is more detail oriented (ie. knows their mash efficiency) could describe how thick or thin the mash should be. I've always just shot for "runny oatmeal", but as a friend recently pointed out, that could mean lots of things to different people. Is it soupy? How does it look? If it matters, I mash between between 148 and 154 depending on the recipe. I normally can nail this perfectly, but the ideal thickness remains a mystery.

Thanks for any insight for an admittedly lazy brewer.

The ideal consistency of the mash depends on the style of beer you are making or how you like your beer.

A thicker mash helps you have more body in your beer. A thinner mash makes for a thinner beer. Thicker mashes inhibit the action of Amalyze in the mash, by having less fluid for it move around in, so it cannot attack as many starch molecules as in a thin mash. Also Amalyze will get stuck to the husk of the grain in a thicker mash and lead to bigger sugar molecules that will survive fermentation and give you a chewy beer as your final product.

Team this up with temperature and you have control of your final product. You want to mash anywhere from 1 qt of water per lb of grain to 2 qt of water per lb of grain. Now those are the two extremes, most people do 1.25 qt to 1.50 qt's per lb of grain. Depends on what you are making.

"A wide range of mash concentrations may be used in brewing. Traditional English mashes for example tend to be rather thick (2-2.5 l/kg; 1 - 1.25 qt/lb) while German mashes tend to be on the thinner side (3.5 - 5 l/kg; 1.75 - 2.5 qt/lb). One reason for the difference is the equipment that these mashes are used in. Traditional English brewing uses a single unheated mash tun that was also used for lautering while German brewers used directly heated mash vessels that require stirring the mash. The mash also has to be pumped from and to a decoction vessel and the lauter tun. The amylase enzymes are more stable in thicker mashes (Figure 8). Which is especially important to the more heat liable β-amylase and as a result thicker mashes give more fermentable worts than thinner mashes when mashing at high mashing temperatures [Briggs, 2004]. But while thick mashes offer better protection for the enzymes, they also inhibit the enzymatic activity through the reduced availability of free water and the sugars acting as competitive inhibitors [Briggs, 2004]. In addition to that the gelatinization of starch is also slower and happens at higher temperatures in thick mashes and as a result thinner mashes are known to give more fermentable worts at normal mashing temperatures" quoted from braukaiser.com

here's a link if you're interested
Starch Conversion - German brewing and more

he's got alot of good info on his site

Anymore I mash 1.7-2 qt/lb. I strike with half the boil volume plus grain absorption/dead space and single batch sparge with the other half. It works fine for me with around 85% efficiency. It won't work so well with your small MLT.