Strike Temperature Definition

[RGHops]

I realize that there are many variables that go into calculating a strike temperature. Things like grain temperature, water to grain ratio, amount of grain, equipment profile, etc. All of which I have entered into the software. In the end, for 10 lbs. of grain where I want to hit a rest temperature of 150 degrees, the software calculates a strike temperature:

Heat 3.8 gallons to 164 degrees for a mash thickness of 1.5 qt/lb.

Does the 164 degrees number represent:

1. The temperature the water in the mash tun needs to be before adding the grain?
2. The temperature the water needs to be heated to before transferring to the mash tun?

I am assuming that it is #1. If the water in the mash tun is at 164 degrees, and I add 10 pounds of grain at the temp in the calculation, that my resting temperature will be 150 degrees (within +/- a degree or two).

Is that correct? My first two mash temperatures have been low by 4-6 degrees, and I am assuming that is because I was thinking that #2 was correct. I was heating the water to 164 degrees, and then transferring it to the mash tun, and then adding the grain.

Just wanted to check to see what everyone else thought before my third batch this weekend.

Thanks!

 

[ChicoBrewer]

It represents 2. I generally nail my strike mash temps using the calculator. Read the FAQ particularly the bit titled "How does the Strike Water calculator work?"

Here is my process.

I use the "Mash Calculator" tab in the brew session.

For my strike - I heat water to about five degrees over my strike temp and pour it into my unheated 5 gallon HLT. I stir it until it cools to the right temp then I dump it in my mash tun. Then I stir in the grain killing off dough balls. I normally nail my mash temp this way. I adjust by either stirring or taking some wort out and heating it then dumping it back. This is rarely necessary though.

I have a problem with the add boiling calculator. It is consistently 5 degrees low ...

 

[Nosybear]

It can actually represent either, depending on your process. If you make allowance for heating the mash tun (as the calculators here do), it's #1. If you preheat your mash tun and use a factor of 0 degrees for heat loss to the tun, it's number 2.

 

[ChicoBrewer]

The FAQ specifically says not to heat the mash tun

"NOTE: The strike calculator assumes your tun will absorb heat (a few degrees will be absorbed by the mash tun, this varies widely by the type of mash tun). Even if you 'pre-heat' the tun with a little boiling water, this may still be the case. Do not stabilize the tun at the calculated strike temperature, and then add grains, or you will probably overshoot."

My experience tells me it is correct

 

[thunderwagn]

If I do biab, my tun is already heated and the strike temp is just to account for the grains. If I use my cooler mash tun, I add several degrees (say 3-5) to pre-heat the tun. I leave it be for 5-10 minutes to get nice and hot, then open it up and cool it to where I need to be for strike temp to add my grains. If you're consistently low 3-4 degrees, I would think you could bump it up that much and be pretty close. Your dry grain temp before adding can make a little bit of a difference also. I know grains I keep in my basement are much cooler than if I keep it upstairs.

 

[ChicoBrewer]

I think the scope of the OP's question is about the calculator.

 

[RGHops]

Ahhh. I think you all have pointed me in the right direction. In the Mash Water Management Tool, there is a setting for Initial Heat Loss. This comes from the equipment profile, and for a plastic cooler mash tun the default is 3 degrees.

Looks like the 164 degrees in my example is based on: 164 - 3 = 161. Based on the amount of grain, grain temp, and ratio, water at 161 degrees would result in a resting temperature of 150 degrees.

I am going to guess that the 3 degrees value for initial heat loss is low in my specific setup. With hoses, valves and the pump, the heat loss is probably more like 7 -8 degrees, so my initial water temp in the mash tun is more like 157 - 156 to start, resulting my lower resting temperature. I need to simply do a test and see what that value actually is (heat water to 164 and then transfer to the mash tun) and then adjust that factor accordingly.

Thanks for the help!

 

[ChicoBrewer]

I need to simply do a test and see what that value actually is (heat water to 164 and then transfer to the mash tun) and then adjust that factor accordingly.

Thanks for the help!

Bingo! Let us know how it turns out. I find the calculator works pretty good for strike water given the adjustments in my profile. I don't know why the add boiling is always off though.

 

[RGHops]

I was able to test things out tonight. Here is what I did.

Mash tun was at 68 degrees. I heated 5 gallons of water to 165 degrees. Then, I connected the hoses and the pump, but instead of connecting to the mash tun I connected to the whirlpool port on the kettle. I turned on the pump on to recirculate the hot water, and found that I lost 1 degree of temperature. Then. I switched connections and pumped into the mash tun, and found that I lost 4 degrees, for a total of 5 degrees. I also determined that the dial thermometer in my mash tun is 1 degree low. I used my Thermoworks Dot thermometer for the water measurements, and compared what it said to the dial thermometer in the mash tun.

This pretty much would explain being low 4 - 6 degrees (5 degree vs 3 degree drop and 1 degree off on the thermometer).

I am going to brew tomorrow evening. Updating my profile with this information, the calculator says I should heat the water to 167 degrees to hit my rest temperature of 150. Given 5 degrees of heat loss, that means my water should be at 162 degrees when I add the grain. I will check that temp, add the grain, and see where I wind up.