Grain Bed Depth

[suzanneb]

i did a search but didn't find much.
i am wondering which type of lauter tun leads to more efficiency. a deeper grain bed that is not as wide(using an upright cooler) or a less deep but wider grain bed (like in a square rectangular cooler.
so does it make a difference. and more importantly why???

 

[JoeBronco]

The larger the surface area your dealing with the more temperature fluctuations you will have. I have a Rectangular "Ice Cube" that i normally fill almost all the way to the top with grain and it works well for me. The dimensions of your mash tun is more about your ability to keep a constant temperature than it is about efficiency, your water, ph and process are what determine that.

 

[rico567]

I cannot see how the shape, per se, of the mash vessel could have any effect on the outcome. It's all about controlling the relevant variables in the mash itself, IMHO.

1. I control my grist by milling the malt myself.

2. I control my water quality by starting with RO (reverse osmosis) water and going from there.

3. I control the pH by using a tablespoon of Five Star 5.2 in the mash. (Some people argue this step is unnecessary; good for them.)

4. I control the temperature by preheating my MLT and covering it with a furniture pad during the mash. This succeeds in holding the temperature loss to only about 3F during a 60 minute mash.

 

[Stephonovich]

If you read How to Brew, Palmer describes (in excruciating detail) how mash/lauter tun geometry affects efficiency. The book is online if you want.

Another effect of grain bed depth is the ability of the grain bed to properly filter the wort. Personally, I use a 70 quart rectangle cooler, which is a bit small for a 5 gallon batch; I've never had any problems. I usually vorlauf for a couple of quarts.