Initial Stike Temp

I did my 3rd all grain brew last night and missed my initial strike temp. by nearly 10 degrees. With my previous two beers I hit the temp. perfectly. The only difference this time, as far as I can tell, was the water to grain ratio. The two batches where I hit my target temp. were 1.25qts/lb. of grain while this one was 1qt/lb. of grain. All three times I filled my 48 quart cooler with hot water and let it sit for 30 minutes before beginning the mash. I also had the equipment profile configured correctly. Finally, my grain was stored inside where I always put my beer stuff so it was at room temperature. Any ideas why I was so far off?

It is hard to tell precisely.

Obviously BeerSmith takes into account the water to grain ratio when you add your grains, so I doubt that is the issue.

Some possibilities:
- Outside air temperature can make a difference
- The temperature of the water you use to preheat your mash tun can make a difference.
- You might want to make sure you have the "Adjust temp for equipment" block checked on the recipe Mash Profile section - particularly if it is checked on some of your recipes and not on others it can make a difference


 That's about all I can think of off the top of my head.  Something has to be different since your two previous batches matched up so well.

Cheers!
Brad

I would verify your equipment profile,  that happened to me and I found out Mash Tun Specific Heat was at .30 (default) and my 10 gal igloo works great at .05 Where I normally have it.

Fred

Please describe Specific Heat and how I might determine the calcs for a particular piece of equipment...Lets say a 1/4 keg??!!

My references cover definitions but not how to make the determination.

Thanks.  

Dave

Specific heat is the amount of energy (in calories) required to raise one gram of material (say stainless steel or plastic for your mash tun) one degree celsius.

 For example, stainless steel is generally around 0.120 calories to raise a gram of stainless steel by one degree celsius.

 Plastic (which varies) is between 0.3 and 0.5 depending on the material, and so on.

 What BeerSmith does is use the weight of the mash tun along with this parameter and the starting and strike temperature to figure out how many calories you need to raise the temperature of the mash tun the desired amount.  (note - it also takes into account how full the mash tun is, since that matters too!).  It then takes this amount of energy and backs out how much additional heating is needed to put that amount of energy in the strike water.

 Obviously the actual number is probably not that precise - since a lot of other factors come into play.  However, the calculation should be in the ball park, and you can make small adjustments to your mash tun specific heat until you are on target for your setup.

Cheers!
Brad