Whacky strike Temp Calculations

Why do different strike temp calculators yield such a variety of answers when programmed with the same variables? I'm getting ready to brew on the 10th (Yeah, I know, about time I worked out the numbers earlier than when the liquor pot is on the fire) and as an experiment plugged all my numbers into about 10 on-line and old-school calculators.

Grain Weight - 14.12 Lbs./6.40 Kg
Grain Temp. - 70F/21c
Strike Water - 17.65 Qts./16.70 L (ratio of 1.25)
Target Temp. - 160F/71c (Jamil's Lagunitas Clone - Yes it's 160F)

The answers I received back varied from 173.1F all the way to 181F!

BeerSmith gave me two answers - 176F using the calculator and 178.1 when I plugged everything into the recipe using My Equipment (10 Gallon Rubbermaid Cooler)

With my last Brew Beersmith's calculator under-estimated the temp but the My Equipment version was closer.

Anyone have a 10 gallon cooler like mine and an accurate calculator?

Thanks.

I'm the wrong guy to be responding to this. Strike temperatures have given me more grief than any single thing since moving to AG. I've finally found a way I can know what strike temperature will produce the proper mash temperature for my setup, given a certain weight of grist, water / grain ratio, etc., and I'm hoping that I can just adjust accordingly when I change recipes. I've found the software I've been using (Brew Alchemy) to be unreliable.

O we're in the same boat. Any mad physics scientisis out there?

All I can tell you is that I only had success after performing the mash tun temperature calibration steps in beer tools pro. The process involves putting a measured amount of water at a specific temp into the cooler then measuring temps over the a few intervals. Once that data and the ambient temp is entered, it kinda knows how the MLT will affect the temp. So far, it's been hitting temps within 1F of my target. I've never used beersmith to its full extent so I don't know if it has an application like that.

Bobby:

do you use a ten gallon rubbermaid mlt?

Thanks

No, I use a converted keg.

I use a 10-gallon Rubbermaid MLT with a SS false bottom, and I don't preheat it. My ProMash calcs for strike water temp are pretty reliable. If I plug your numbers in, I get 177F for the strike water temp.

Flyinghorse:

that's one of the choices I had behind box #3 of one of the calculators. Palmer's formula gave me 174. I'll let you know how 177 woos out. Thank you.

I use the green bay rackers calculation for the most part. Specifically, I heat it up to 5F over GB strike temp, place the water in my cooler and cover the lid for 5 minutes. Then I uncover and stir it down to the rackers suggestion. With that done, their strike temp makes the mash within 1F-2F of target for me. Additional stirring can quickly take care of that small margin.

hal:

GB Racker's result seems to be pretty close to Flyinghorse's. I'm going with 177. I usually preheat the MLT before I add my water. I also heat the water a little higher and then let it cool down to the strike temp before doughing in. After ten or so AG batches I still seem to be learning.

I have a 10 gallon Rubbermaid MLT, my temps are dead on each time.

Pol:

Yeah, but you're a damn super-hero-all-electric, friggen brewing boy genius. What about us stuck-on-the-ground mortals who throw the dice every time we sprinkle that grain into the MLT abyss?

But seriously, how ya been? Thanks for checking in. Does your Promash say 177 for this grain bill? I'm thinking 177.

Meh... I get 174F

That being said... I heat to strike PLUS 10F, then let it heat the MLT, when the water reaches 174F Id mash in. I hit my temp. each and every time.

This is from ProMash

ProMash sayes that if you use 177F water, you will rest at 163F

Pol:

Having saved me from certain self implosion that first batch (let's just keep that between you and me, ok?) I'm going to flip all the cards and award the strike prize to you. If you say 177 is too high, then 174 it is. Anyone else want to dispute that, you'll have to take on me and Pol together, texas steel cage death brew off.

Thanks Pol.

Champurrado said:

Pol:

Having saved me from certain self implosion that first batch (let's just keep that between you and me, ok?) I'm going to flip all the cards and award the strike prize to you. If you say 177 is too high, then 174 it is. Anyone else want to dispute that, you'll have to take on me and Pol together, texas steel cage death brew off.

Thanks Pol.

Click to expand...

All I know is this is what I do, and it works. Strike calculators are all over the place and I have read more than one thread here about some guy that used GBMashers calcs. and totally missed thier temp. ProMash works in my system.

One way I took out some variables was going into the ProMash parameters and setting my MLT thermal mass to 0.0

Most calculators have some default value in there, I took that out. It really doesnt matter in my process since my MLT is at strike temp when I mash in.

Gotcha. Gracias.

I checked Beersmith (I also use a 10 gal round cooler MLT). I show 17.65 qt at 173.1F. However, I tell Beersmith not to adjust for equipment. I'm always within about 1F of mash temps with this process:

1. Heat water to 173.1F + 15F = 188F
2. Dump water into MLT (no grain yet) and ignore for 15 minutes
3. Stir, test temp, stir, test temp, ..., until water temp = 173.1F
4. Dump in grain, stir like crazy, ignore for 5 minutes, then check temp

I've found this to be very reliable. The two most important parts are putting the grain in after the water and waiting long enough for temps to stabilize before checking.

RunBikeBrew said:

I checked Beersmith (I also use a 10 gal round cooler MLT). I show 17.65 qt at 173.1F. However, I tell Beersmith not to adjust for equipment. I'm always within about 1F of mash temps with this process:

1. Heat water to 173.1F + 15F = 188F
2. Dump water into MLT (no grain yet) and ignore for 15 minutes
3. Stir, test temp, stir, test temp, ..., until water temp = 173.1F
4. Dump in grain, stir like crazy, ignore for 5 minutes, then check temp

I've found this to be very reliable. The two most important parts are putting the grain in after the water and waiting long enough for temps to stabilize before checking.

Click to expand...

This is my mehtod too

I calculate 174, and I'm usually dead on. I made the most absurdly complicated brew spreadsheet a few years ago and have no idea how I arrived at this calculation, but here it is: 0.2/(infusion qt/lb) * (target temp - grain temp) + target temp.

0.2/1.25 * (160 - 70) + 160 = 174.4

My spreadsheet is set up to calculate up to three infusions and calculate the sparge water needed to meet the total boil volume. Anyway...absurdly complicated but somehow accurate.

RunBikeBrew said:

1. Heat water to 173.1F + 15F = 188F
2. Dump water into MLT (no grain yet) and ignore for 15 minutes
3. Stir, test temp, stir, test temp, ..., until water temp = 173.1F
4. Dump in grain, stir like crazy, ignore for 5 minutes, then check temp

Click to expand...

A couple questions about this process, as I've just done my first AG batch and the strike temp issue was really the only problem I encountered:
1. I'm assuming you cover the MLT during the "ignore" phases, right?
2. If the temp is high (or low) after dumping in the grain, stirring, and ignoring for 5 minutes, would you adjust with cold (or boiling) water and repeat the stir/ignore 5 minutes/test temp routine?

Artguy - I cover the MLT during step 2, then uncover during step 3 as required to get it to cool off. I've found it's much easier getting the water to cool off than trying to increase the temperature. Step 4 is always covered; that's when I want to hold temps. If my temps are off (which hasn't happened yet with this method), I would add boiling water or cold water per Beersmith adjust mash calcs. I would definitely use the stir/ignore/test routine, though. I used to drive myself crazy by checking the temp too early, before everything stabilized.

I think Palmer's strike temp calculation gave same 174 result. Beer smith is high because it's adjusted for default using "my equipment". Since I don't usually brew same beer twice, at least not yet, every brew day requires new calculations.

Someday i'm going to have a lot of notebooks filled with accurate numbers.

Champurrado said:

I think Palmer's strike temp calculation gave same 174 result. Beer smith is high because it's adjusted for default using "my equipment". Since I don't usually brew same beer twice, at least not yet, every brew day requires new calculations.

Someday i'm going to have a lot of notebooks filled with accurate numbers.

Click to expand...

Or an accurate calculator!

Or just ask Pol!

Champurrado said:

Or just ask Pol!

Click to expand...

But what if he is actually working?

thisjrp4 said:

I calculate 174, and I'm usually dead on. I made the most absurdly complicated brew spreadsheet a few years ago and have no idea how I arrived at this calculation, but here it is: 0.2/(infusion qt/lb) * (target temp - grain temp) + target temp.

0.2/1.25 * (160 - 70) + 160 = 174.4

My spreadsheet is set up to calculate up to three infusions and calculate the sparge water needed to meet the total boil volume. Anyway...absurdly complicated but somehow accurate.

Click to expand...

I made an equally complicated spreadsheet, and mine has the same formula. I use it, and have pretty good results. It comes from Palmer's "How to Brew" Chapter 16.3:
http://www.howtobrew.com/section3/chapter16-3.html

I used the calculation in our demo copy of Beersmith yesterday to calculate the water temp for our first shot at the Centennial Blonde. It was dead on. Our brew rig is a 10 gal Rubbermaid cooler as well. We hit the value by going into the details section of the mash setup. I entered the temp of the grains and the temp we preheated the cooler to. It worked great. However it did significantly alter the strike temp after I made the adjustments based on the actual temps. I'm gonna spend the money on Beersmith.