Originally Posted by hogie1980
Thanks for telling me about this in my other post. Trying it out now and I have a few questions... What is the water to grain ratio it's using? Does it assume a 10% absorption? Is it possible to unprotect the Strike temp because I was planning on 170F?
The water to grain ratio is a calculation designed so that you will obtain half of your boil volume from your mash and the other half from your sparge. The number you see in the cell is in gallons. To convert it to quarts you would multiply by 4. My work in this area of the brew chart was based on the work/research of Ken Schwartz and Kai at braukaiser.com Their work/research on batch sparge brewing shows that our best efficiency is obtained this way. You can read more about this at:
Ken Schwartz - http://home.roadrunner.com/~brewbeer/files/nbsparge.html
Kai - http://braukaiser.com/wiki/index.php/Batch_Sparging_Analysis
It assumes an absorption of .125 gallons per pound of grain.
No reason to unprotect the strike temp cell really. If you don't want to use the calculation within the cell just use the amount you prefer instead. That cell doesn't effect any of the other calcs. I would tell you that my experience and most everyone I've interacted with have found it to be very accurate. It is science/math so assuming you are inputting your figures correctly and pre-heating your mash tun it should work well. My recommendation is always to go into your mash tun about 5 degrees higher than the calc tells you and allow it to come down to about 2-3 degrees higher than the recommendedtemp. That will alleviate any concern about further heat loss in your tun. At that time begin adding your grains while stirring well. As you're stirring monitor the temp and close it up when you hit your desired mash temp. This process eliminates the concern of being too low with your mash temp which is a much bigger pain in the ass than being a little high. If you're a little high you just keep stirring while it's open until you reach the temp you want.
If you go to the brewday tab you'll see the brewer schedule as well. This details my process which may be of some help. You can of course re-write that if you'd like as well.
If you have any further questions please don't hesitate to ask. Appreciate any feedback as it allows me to keep improving this thing. The last time I posted a version there was some great feedback which propelled it to where it is now. It's essentially turned into a homebrewtalk thing and not just my thing which is pretty cool.