[Pi]

Apologies if I am in the wrong group for this thread
I have about 6L deadspace to account for all wort on the "other side" of the false bottom. About 1L is in the pipes etc. So since I am recirculating my liquor, do I have much say in the matter when it comes down to enzyme activity in my mash?
Forming a recipe, if guidlines tell me to shoot for a thickness of 1 qt/lb/gal., for 10lbs. grain I would do 10 qts+my deadspace (about 6L.) so 16L. right? But if my liquor is recirculating, just where are the enzymes at, grain or liquor, or both?

[tschmidlin]

The soluble enzymes are in the liquor.  The liquor is in the pipes, under the false bottom, and throughout the grain.  I'm not sure exactly what you're concerned about here, but my main concern would be the temperature of the liquor in the RIMS system and if it is getting hot enough to denature the enzymes.

[morticaixavier]

I believe you have it correct. it would be 16 liters. But also don't worry that much. The enzymes will do their work just fine right up to and exceeding 2 qt/lb. even 3 I have read. I think often when someone puts 1qt/lb it's either caue they are doing no sparge and thats all they need to get their preboil or because that's all that will fit in the tun. but I do not recirc or have deadspace in my tun so others may know better.

Like Tom^^^

[bluesman]

Yes...you are right.

10lbs of grain at 1qt/lb = 10qt which is approx 10L + 6L (deadspace) = 16L of water required

There will be plenty of enzyme accessibility to the starches for conversion.

[Pi]

 Thanks for putting this to "rest". Did a little reading last night and from what I can tell, mash thickness has little effect; and I should be more attentive to temperature and rest lenghts.

[malzig]

mash thickness has little effect; and I should be more attentive to temperature and rest lenghts.

Absolutely, but don't be afraid to go thin if you are getting low conversion efficiency.  As xavier said, most thickness decisions were probably made by grist quantity and tun size, not by a particular effect on the finished beer.  This homebrewer "tradition" of mash thicknesses down around 1-1.25 qt/# is a rather eccentric one.

[richardt]

http://braukaiser.com/wiki/index.php?title=Effects_of_mash_parameters_on_fermentability_and_efficiency_in_single_infusion_mashing

Thinner mash is better (efficiency and attenuation/fermentability).

Tom's point regarding RIMS should be heeded--if your RIMS essentially boils the wort and dumps it into the mash tun, then you're denaturing the enzymes.  However, if your RIMS gently heats up the wort to the desired temp and recirculates it back into the mash tun, then you should have no worries.  It all depends on flow rates and energy input levels.

For me and many others, single- (or step-) infusion in a rectangular cooler is less stress on the psyche.

[Pi]

if your RIMS essentially boils the wort and dumps it into the mash tun, then you're denaturing the enzymes...

Thermocouple is just out of the heating unit (An electric water heater element in  a 14"X1 1/2" Copper pipe) and never overshoots rest temp. And, as a saftey, the heater will only heat if the pump is running. So no worries there. I average 81% effeciency, but sometimes I get like 86-88%. Guess i should review my notes. I thought the flux had more to do with grain types.

[wildknight]

I worried about this too with my system, as it holds 2 gallons under the false bottom.  However, I don't feel that the quality of the beer is any different than when I used a bazookah screen and less total water. 

The main concern, to me, about higher liquid to grain ratios manifests in the pH.  The grain supplies the organic acids and the water supplies the calcium and alkalinity.  If you have a lower total volume of water, then the available alkalinity is less and easily consumed.  If you have to use more water, then there is more residual alkalinity to impact pH.  Unless you have very alkaline water, this is a minor problem, maybe only 0.1 pH units.  However, if you have moderate to high alkalinity, then the pH could be off (basic) by 0.2-0.4, which could put you in the 5.8 pH range and enzyme activity could be reduced.  You can either add a little acid to correct or simply give the enzymes a little more time to work.  If making dark beers with dark kilned, acidic grains, then you probably won't ever notice.