Pre-heating MT

How long should I pre-heat the MT from room temp? Currently using 2 gal boiling water for half hour. Brew Smith asks for MT temp. Any thought on how to accurately measure the MT temp? Dump out the water and tape thermometer probe to inside wall?

ImperialStout said:

How long should I pre-heat the MT from room temp? Currently using 2 gal boiling water for half hour. Brew Smith asks for MT temp. Any thought on how to accurately measure the MT temp? Dump out the water and tape thermometer probe to inside wall?

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I normally just overheat my strike water to a few degrees more than my target and leave it for 5 minutes. I rarely lose > 2 degrees F p/hr.

I would just measure the water temp in the tun before you drain and use that. I can't see why it's all that important but who knows.....

I add my entire mash water addition to the tun at a few degrees above what BeerSmith indicates I need to heat up the tun+grain, assuming both start at room temp. I check the temperature after 10 mins, add a tiny bit of cold water if it needs to cool a little, then mash in. After mash-in, I stir well and measure temperature. Put lid on and let it go. I do a mid-mash hot water addition to get the temp back up to the goal, so I generally measure twice. Once in the beginning, once around 30 minutes in. In BeerSmith, I note the water temp it tells me I need assuming room temp water and mash tun (this tells me around how hot the mash water needs to be initially). Then I change the temperature of the mash tun until it matches the required water temperature for mash-in (this tells me what temperature the water I already have added to the mash tun needs to be after I have pre-warmed the tun). I go a bit hotter on the mash water at first so I can dial down right before/after adding the grain.

I use a gallon or so of water from my HLT about 10 minutes (big guess here) before my strike water comes to temperature. Then when the strike water is ready I dump the preheat water and start my mash. This works fine for me except in the winter when I get it hotter, leave it longer and strike a little higher.

The important thing is to get your mash temperature right without using a lot of hot or cold water for correction. How you do it is unimportant.

Since I don't use BeerSmith, can somebody tell me why it matters what your mash tun temperature is?

Derek1985 said:

Since I don't use BeerSmith, can somebody tell me why it matters what your mash tun temperature is?

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A cold mash tun will absorb a certain amount of heat. If someone plans to just add hot water and room-temp grain to the mash tun, BeerSmith estimates what temperature the water needs to be and can be adjusted based on the temperature of the mash tun.

wardens355 said:

A cold mash tun will absorb a certain amount of heat. If someone plans to just add hot water and room-temp grain to the mash tun, BeerSmith estimates what temperature the water needs to be and can be adjusted based on the temperature of the mash tun.

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Yeah I get the pre-heating aspect. I was just curious why it mattered in BeerSmith, which you answered.

Seems like a silly thing to use software for!

Derek1985 said:

Seems like a silly thing to use software for!

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I find it rather useful. At a minimum it reminds the brewer that your water temperature will drop from when you first pour it in to when the temperature of the tun and water equalize.

wardens355 said:

I find it rather useful. At a minimum it reminds the brewer that your water temperature will drop from when you first pour it in to when the temperature of the tun and water equalize.

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That's true. I use the thermal equation in my step mash calculator to get my strike water temp which ultimately is doing the same thing I guess.

Derek1985 said:

Seems like a silly thing to use software for!

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You do not use the software to do THIS. You use the software to calculate about everything you need to know about an all-grain batch...one of those many things is what your strike water temperature should be. It also gives you (non-exhaustive list):
Expected Pre-boil gravity
Expected OG
mash thickness
strike water volume
sparge water volume
expected final volume
expected FG
expected IBU's

With all this information after about 4-5 brew session you have tweaked things to match your process and equipment making "hitting the numbers" in the future much easier.

I personally do not use that specific software but almost any of them will increase you predictability once dialed in. This in turn makes recipe creation easier and more accurate.

Onkel_Udo said:

You do not use the software to do THIS. You use the software to calculate about everything you need to know about an all-grain batch...one of those many things is what your strike water temperature should be. It also gives you (non-exhaustive list):
Expected Pre-boil gravity
Expected OG
mash thickness
strike water volume
sparge water volume
expected final volume
expected FG
expected IBU's

With all this information after about 4-5 brew session you have tweaked things to match your process and equipment making "hitting the numbers" in the future much easier.

I personally do not use that specific software but almost any of them will increase you predictability once dialed in. This in turn makes recipe creation easier and more accurate.

Click to expand...

I understand and am familiar with the mathematics of brewing. I have my own spreadsheet I use. I misunderstood the necessity for the mash tun temp is all.

In Beersmith when you tell it the temperature of the mash tun it will adjust the temperature of your strike water due to expected loss in temperature so that you should be at mash temperature when everything equalizes.

If you use the current temperature, say 80 degrees in the summer, or 32 outside mid winter Beersmith will try to adjust your strike temperature so that you are at your, say - 152 degree mash temperature when the grain and tun absorb the heat.

If you preheat it makes the calculation unnecessary or at least the difference is smaller so the error should be less.

kh54s10 said:

In Beersmith when you tell it the temperature of the mash tun it will adjust the temperature of your strike water due to expected loss in temperature so that you should be at mash temperature when everything equalizes.

If you use the current temperature, say 80 degrees in the summer, or 32 outside mid winter Beersmith will try to adjust your strike temperature so that you are at your, say - 152 degree mash temperature when the grain and tun absorb the heat.

If you preheat it makes the calculation unnecessary or at least the difference is smaller so the error should be less.

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I just pre-heat and then use the basic thermal equation to calculate my strike water temp.

End result is ultimately the same.

I heat my strike water to 170F and transfer to the MT with my reflectix wrap already on. I will then stir in my mash mineral additions and continue stirring (takes a few minutes) until I hit my strike temp (usually around 164-166F). Dough in, hit 152-154F mash temp, and that will drop 1, maybe 2 degrees over the entire mash.

This is on a keggle for the record.

I only preheat my tun in cold weather. During the warmer/hot months I generally stick w/ what BS suggests.
Since I start w/ 120° water I use a few gallons of that to preheat my tun when needed.
I save this water for cleanup after I empty my tun & fill w/ heated strike water @ mash in.

I don't preheat, beersmith does all the calculations for me.
I've messed around with the numbers in beersmith and the temperature of the mash tun doesn't really seem to make much of a difference anyways, maybe 1 degree from room temp to preheated temps, the grain temp however makes a big difference.

Natdavis777 said:

I heat my strike water to 170F and transfer to the MT with my reflectix wrap already on. I will then stir in my mash mineral additions and continue stirring (takes a few minutes) until I hit my strike temp (usually around 164-166F). Dough in, hit 152-154F mash temp, and that will drop 1, maybe 2 degrees over the entire mash.

This is on a keggle for the record.

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This is exactly how I do it as well (in a cooler). I also lay a piece of aluminum foil across the top of the mash which seems to help with keeping the temperature steady for an entire mash. I usually don't even lose 1 degree over a 60 min mash.

Another added benefit of the aluminum foil is that once it is time to drain first runnings I poke a bunch of holes in the foil with my temperature probe, and then when pouring back the wort from vorlaufing i pour right onto the foil and it keeps it from disturbing the grain bed.

Its all just tips i picked up from reading HBT every damn day. I used to hate mashing and missed my temps all the time. After trying this process mashing couldn't be simpler!