Promash Strike Temp

[Georgedgerton]

Recently I have broken from old habits and stared to try a few batches using ProMash. One thing I find with the strike temperature is even with the thermal mass of the mash tun set to 0 I still consistently wind up with a strike temperature 1.5 degrees higher than the figure ProMash works out.

Any thoughts on this?

 

[ausdb]

Recently I have broken from old habits and stared to try a few batches using ProMash. One thing I find with the strike temperature is even with the thermal mass of the mash tun set to 0 I still consistently wind up with a strike temperature 1.5 degrees higher than the figure ProMash works out.

Any thoughts on this?

How accurate is your grain temp, and can you try and offset it?
I find it works well doing infusion mashes in an eslky MLT

 

[gap]

There are a few variables---

Is your thermometer accure in measuring the temperature of the water and the mash

Is the volume of your mash water accurate - have you a calibrated vessel for measuring the amount of
strike water you use.

Regards

Graeme

 

[Georgedgerton]

I have measured the temp with a second digital thermometer of the same make and variation of .1 between them is not unusual, dependent on the range being measured, so I doubt that is a problem as it would mean there is an error of 1.5 degrees between the initial measurements and the desired strike temperature.

Definitely will check the water volume as that most certainly would have an effect though it is unlikely it would be so far out as to cause a 1.5 degree difference.

So far the way I have handled it is just to compensate for the difference as it is fairly consistent, just one of those things that I would like to find an answer for.

Thanks

 

[Guest Lurker]

Something isnt right and I dont think it is Promash. If I know that I have used the volumes and temps indicated by Promash, but measure a different starting temp, I conclude that I have measured an uneven bit of the mash, or there is a problem with the thermometer. When I check at the end of the mash when everything is even I always find that Promash was right.

 

[Georgedgerton]

I think your right and I am starting to get suspicious of the thermometers.

Some years back I had a bit to do with measuring temperature in both glass and electric kilns. The electronic wizardry that works out the information from the probe does not work in truly linear fashion, and you can get jumps in the readings. In my case I am wondering if the thermometers used are jumping the 1.5 degrees in temp range I am measuring. For instance the manufacturer might say the thermometer has a + - reading of .1 but it may not have that accuracy across it's entire range, and as both are from the same manufacturer and model then it would be possible both instruments have the same inherent deficiency.

My next move is to obtain a thermometer of a different manufacturer and make a comparison, will keep informed if I discover anything of interest.

 

[t2000kw]

If a lab grade thermometer that's certified to be accurate to within a fraction of a degree isn't available at a reasonable cost, you might look for a cooking thermometer in a kitchen or restaurant supply store.

When I buy one of these for cooking or brewing, I look at what temperature they are reading in the store and buy one in the middle of the readings, not including the outliers that are way off from the rest. But a lab grade one would be a nice thing to have to get an idea how close my thermometers are to the real temperature.

 

[dreamboat]

Do you heat your water in your mash tun - ie is your mash tun at strike temperature before you start? If so, this adds an amount of energy to your system in the form of the hot mash tun material. I have a stainless steel mash tun (urn) but it has thin walls and the amount of material in it is quite low, but you may be in a different situaltion.....


dreamboat

 

[TidalPete]

Do you heat your water in your mash tun - ie is your mash tun at strike temperature before you start? If so, this adds an amount of energy to your system in the form of the hot mash tun material. I have a stainless steel mash tun (urn) but it has thin walls and the amount of material in it is quite low, but you may be in a different situaltion.....


dreamboat

Dreamboat might have something here. To get "0" thermal mass in your mash tun at the start you need to pre-heat it in some way. With my old MT (A Coleman cooler) I found that a litre of boiling water left in it for a couple of minutes then tipped out before adding the grain & liquor worked well in getting my initial temps correct at the start of the mash.

TP

 

[Georgedgerton]

I follow pretty much the same lines as TidalPete by taking any chill of the tun with about a litre of hot water to try and get it to about the same temp I have measured the grain at. Not perfect by any stretch of the imagination, so I guess errors could also creep in at that point

 

[mckenry]

I use Beersmith, so no expert by any stretch. But, (and yes, grammar nazis, I can start a sentence with a conjuction) Beersmith has the default grain temp set at 22C, and if you select adjust temp for equipment and your grain is 9C as it is in my garage, you're way out.
Are there any settings for adjusting temp using gear and the default grain temp is 1.5C below what it really is?
mckenry?

 

[Georgedgerton]

The ProMash calculator Has:

Thermal mass of tun
Total grain weight
Total water
Water / grain ratio
Desired strike temp
Grain temp
=
What strike water temp should be
Total mash volume

Any alterations to the above six parameters then alters what the strike water temp should be
Though not perfect I try to get the tun temp as close as I can to the grain temp (usually about 20C) and set the thermal mass to 0

Though I haven't sourced a known accurate thermometer at this point I am still inclined to think that is where the problem is going to be

 

[dreamboat]

I am not sure how thermal mass of tun comes into the calculations, however I would have thought that to have a mash tun thermal mass of 0, you would have to have the temperature of the mash tun at your the temp of your first rest. If it was at strike water temp it would add some energy (affected by the temp, mass and material of the tun), and any lower than that it would draw some energy out of the system based on the same factors....


dreamboat