Mash tun strike temperature

[AFewTooMany]

Recently received a 50l high end mash tun from the brew builder. Whilst it is superb, I have missed my mash temp by a fairly big margin both times I've used it. Anybody with either a thermo pot or high end tun have any wisdom? Would simply rinsing it with boiling water be sufficient?

[orlando]

Recently received a 50l high end mash tun from the brew builder. Whilst it is superb, I have missed my mash temp by a fairly big margin both times I've used it. Anybody with either a thermo pot or high end tun have any wisdom? Would simply rinsing it with boiling water be sufficient?

There are strike water calculators all over the web, there's one built into BeerSmith. Have you tried any of those? I have the same pot as you but use my RIMS to heat the strike water in the Tun, which of course heats the Tun too so only have to take into account grain temp.

[BenB]

Do you use something like Beersmith to work out your temperatures? If so you can adjust for different materials. I don't use boiling water anymore- I just run about 15L out of the HLT into the mash tun when I'm almost at strike temp, let it sit for 10 then pop it back in the HLT. The PID controlled HLT quickly gets back to temp and the mash tun doesn't have much time to cool down.

[Sura]

Give some strike water you normally use (temperature and amount) without grist in your tun, and after it take a look at the temperature. Simply add the difference you get to your next strike water temperature.

[Kev888]

If you fill the mash tun with strike liquor prior to adding the grain, then you can test to see if the strike temperature is correct (and if necessary adjust) before adding the grain, using for example andy's strike temperature calculator to determine the target. That may take a bit of faffing about to adjust, but it happens before the mash and so is much more relaxed than trying to do it once the mash is on.

It is important to let the mash tun heat through for a while before taking the measurement, as if the tun is still warming up then the liquor temperature will be dropping slightly. A stainless tun will likely take more warming than a plastic one, so to achieve the same strike temperature you may need to use either slightly higher initial liquor temperature or else pre-warm the tun (say with a kettle-full of boiling water or similar).

If you want to be more considered about it or if you add the liquor after the grain (e.g. underletting) then you need everything to come together more perfectly first time. That means knowing how much heat the mash tun will suck from the liquor, in addition to the grain. This will not be a set amount, since the mash tun's initial temperature will change it, but by keeping records of initial mash tun temperature, initial liquor temperature and the resulting temperature when combined you can build up a pretty good picture to help you estimate this. To take that a step further, you can use these results to work out the thermal characteristics of the tun - its equivalent specific heat capacity - which can be included in the strike temperature calculation alongside the grain.

[guypettigrew]

Andy's strike temperature calculator on here works well for me.

It usually tells me my strike temperature needs to be about 76C. Experience has shown me the liquor needs to be about 85C when it goes into my double skinned shiny mash tun. This is because my brewshed is outside and open fronted so, at the moment, it's about 0C in the morning when I go out there to start a brewday.

The tun is given about 10-15 minutes to stabilise then the temperature is fine tuned to the desired level using (usually) a bit of cold water.

Guy

[Fil]

I have a similar issue shifting from a plastic cold box tun which needed a single kitchen kettle full of off the boil water to preheat, and a strike temp of 71c to let me mash in at a nice 67c.

Now with a big 80l thermopot tun things are much different, the much larger internal SS surface needs a lot more heat input to bring upto temperature, Ive toyed with ideas such as employing a dry electric heatsource like a Infra red bulb or trace cable. but have instead used 10-20l of hot hlt liquor @71C before draining back into the HLT via a handy FV before reheating upto 73c to strike.

my first brew which involved 3 x kettle fulls to preheat the tun and FB and a strike of 71C and then about 5 kettles of off the boil hlt liquor thinning the mash significantly before a 66C temp was hit..

[AFewTooMany]

Cheers for all the replies. Yeah I used strike calculators when I BIAB. The problem is definitely the additional mass of the new tun. Just looking for a ballpark increase over the value stated by the calculator

[Chug]

I had the same problem when using a different pot, I had it too hot first time and needed cold water, then too cold the second time and the third time I got it spot on, practice makes perfect, get more brews on!

[Kev888]

Cheers for all the replies. Yeah I used strike calculators when I BIAB. The problem is definitely the additional mass of the new tun. Just looking for a ballpark increase over the value stated by the calculator

If you add the liquor/water to the mash tun (and let it stabilise) before adding the grain, the calculator's target strike temperature will be correct and should not need adjusting. The strike temperature is the target 'after' the mash tun and liquor have stabilised, which is then only cooled by the grain (to reach mash temperature). It is therefore independent of the mash tun used.

The only thing you should need to do is increase the initial temperature of your liquor in order that you can still get the calculator's strike temperature (when the metal tun has taken more heat out). Trying to account for this on the fly by using a higher than calculated strike temperature is much harder to gauge.

(Thats unless you are underletting or similar; situations where the liquor meets the tun and grain in the same step are more complicated).

[AFewTooMany]

Cheers for all the replies. Yeah I used strike calculators when I BIAB. The problem is definitely the additional mass of the new tun. Just looking for a ballpark increase over the value stated by the calculator

If you add the liquor/water to the mash tun (and let it stabilise) before adding the grain, the calculator's target strike temperature will be correct and should not need adjusting. The strike temperature is the target 'after' the mash tun and liquor have stabilised, which is then only cooled by the grain (to reach mash temperature). It is therefore independent of the mash tun used.

The only thing you should need to do is increase the initial temperature of your liquor in order that you can still get the calculator's strike temperature (when the metal tun has taken more heat out). Trying to account for this on the fly by using a higher than calculated strike temperature is much harder to gauge.

(Thats unless you are underletting or similar; situations where the liquor meets the tun and grain in the same step are more complicated).

Should have said I under let. Ended up filling the mash tun with over heated water. Took a note of the temp drop. Cooled with ice to strike temp, emptied water back into hlt, added grain and then pumped water back in from beneath. What a farce

[Kev888]

Ah, that explains it. Yes, a very different situation; many of the temperature calculators don't allow for the cooling effect of the tun to happen after/during the strike, its very specific to the mash tun, and changes depending on the temperatures (its not a fixed offset) so gets complicated.

Some people find that pre-heating the tun is sufficient to then ignore it, but others (especially with heavy duty mash tuns) do factor it in properly. With tests of how much the tun drops the temperature of known volumes of water, you can work out its thermal characteristics (it may be convenient for the maths to then express these as if they were an equivalent volume of cool water). Back in the day I had a cold garage and thick steel tun so this was necessary, but sadly I can't recall the exact details.

[Sura]

Its quite simple:

Ts = Tt + (0,32 * kgMalt + Mt) * (Tt-Tr) / Ms

Ts = Striketemperatur (I add additional 1°C to the target temperature for stirring at mash in)
Tt = Targettemperature
Tr = Roomtemperature
Ms = Strikemass (kg)
Mt = Mass of the tun

So, when you put in no malt and measure after "strike in" only water in the cold tun, you got the thermic mass:
Mt = (Ts-Tt) * Ms / (Tt-Tr)

Example: (Strikewater is 20l @ 65°C -> in the tun only 61°C)
(65°C-61°C) * 20kg / (61°C-20°C) = 1,95kg

[Fil]

Its quite simple:

Ts = Tt + (0,32 * kgMalt + Mt) * (Tt-Tr) / Ms

Ts = Striketemperatur (I add additional 1°C to the target temperature for stirring at mash in)
Tt = Targettemperature
Tr = Roomtemperature
Ms = Strikemass (kg)
Mt = Mass of the tun

So, when you put in no malt and measure after "strike in" only water in the cold tun, you got the thermic mass:
Mt = (Ts-Tt) * Ms / (Tt-Tr)

Example: (Strikewater is 20l @ 65°C -> in the tun only 61°C)
(65°C-61°C) * 20kg / (61°C-20°C) = 1,95kg

Whats simple to some can cause head scratching in others, so assuming i perform a 20l temp drop test with my tun and derive the same Mt, with a 10kg grain bill, and a 67C target mash temperature and 16C room temp. And its Monday Morning..

Ts = 67 + (0,32 * 10 + 1.95) * (67-16) / 31

Ts = 67+ (5.15) * (51) /31
Ts = 67 + 8.47
75.47C Strike Temperature..

I guess its assuming the grain is at room temp too.
where is this from? if its got credible pedigree, or simply works its worthy of stickying or recording in an easy to find spot..
great contribution @sura

[Sura]

Yes, mash is at room temperature.
There is one problem..... when you splash in the Strikewater, it already isn´ t the measured strike-temperature. So you have to splash carefully, or figure ist out and correct it...
The formula is like a base: You have to put personal thinks in. (So i did with the additional 1°C for stirring....)