Mash temp dropping by like 6F

[urg8rb8]

I use an igloo cooler. I measured the temp after mixing the grains and I got 154F, my target temp. However, 45 mins later I decided to take a temp reading and it was at 148F. I have never seen this before. What did I do wrong?

 

[kh54s10]

Colder where your mash tun is? You probably didn't do anything wrong. Pre-heat, insulate by wrapping in blankets.

 

[urg8rb8]

Colder where your mash tun is? You probably didn't do anything wrong. Pre-heat, insulate by wrapping in blankets.

Yeah it's about 20 degrees colder than normal. How much do you think body is going to be affected by this?

 

[balrog]

Conversion happens fairly soon based on milling making starch bits more readily available for gelatinization. By 45min things are very likely done and the critical temp hold period is long passed.

 

[urg8rb8]

Conversion happens fairly soon based on milling making starch bits more readily available for gelatinization. By 45min things are very likely done and the critical temp hold period is long passed.

Hopefully all is well. Bet might be thinner than planned.

 

[dmtaylor]

That's normal. Aim a few degrees higher next time. Then on the average your mash temp will be where you wanted it. That's what I do.

 

[urg8rb8]

That's normal. Aim a few degrees higher next time. Then on the average your mash temp will be where you wanted it. That's what I do.

Normal because it's colder than usual outside?

 

[dmtaylor]

Normal because it's colder than usual outside?

Normal because unless you preheat the mash tun to mash temperature, it probably started at 60-70 F, then you added grains stored at 60-70 F and hot water, then stirred well, but the mash tun and grains still take a few extra minutes to warm up... and then the mash tun is NOT a perfect insulator and will lose some heat on its own as well, assuming you are not living in a 150 F environment or thereabouts.

 

[urg8rb8]

Normal because unless you preheat the mash tun to mash temperature, it probably started at 60-70 F, then you added grains stored at 60-70 F and hot water, then stirred well, but the mash tun and grains still take a few extra minutes to warm up... and then the mash tun is NOT a perfect insulator and will lose some heat on its own as well, assuming you are not living in a 150 F environment or thereabouts.

Yeah, it's usually 80 here. It's possible I didn't allow the mash ton to warm up enough. I'll try to be more careful next time.

 

[applescrap]

I remain totally and completely unconvinced as to the importance of mash temperature related to taste. There are scientifically measurable differences between 147 and 164 degree mash temps. In fact one beer finished 16 gravity points higher than the other in brulosophies study at those two temps. One was 3.3 abv and the other 4.9 abv. Turns out that only 12 in 33 who tatsed it could reliably pick the odd beer out. This is the second time they did this test with the first yielding the exact same results.

Yet, I have had people here or in bars tell me they can taste 1 degree difference in mash temps. Others build systems, expensive systems to recirculate becuase they feel there is value in maintaining mash temps. So you are free to use this info as you like. I use this data to mash lower because if they are going to taste the same anyways (minus confirmation bias) more abv seems the way to go so 148 to 150ish sounds perfect to me.

 

[SteveH aka shetc]

I remain totally and completely unconvinced as to the importance of mash temperature related to taste. There are scientifically measurable differences between 147 and 164 degree mash temps. In fact one beer finished 16 gravity points higher than the other in brulosophies study at those two temps. One was 3.3 abv and the other 4.9 abv. Turns out that only 12 in 33 who tatsed it could reliably pick the odd beer out. This is the second time they did this test with the first yielding the exact same results.

Yet, I have had people here or in bars tell me they can taste 1 degree difference in mash temps. Others build systems, expensive systems to recirculate becuase they feel there is value in maintaining mash temps. So you are free to use this info as you like. I use this data to mash lower because if they are going to taste the same anyways (minus confirmation bias) more abv seems the way to go so 148 to 150ish sounds perfect to me.

Have been working my way through Palmer and Zainascheff's Brew Strong podcasts, and one of the common themes is to not get hung up on mash temp - if you are reasonably close then don't worry about it.

 

[Lefou]

Traded in my 10gal Igloo for a 7.5gal stainless steel kettle with a valve, false bottom, and thermometer.
This way I know temps can be held stable when adding grain to the strike water. This also allows application of direct heat and step mashing on the stove. It's more or less a compromise, eliminating water additions for step mashing because the cooler can't be directly heated.
The stovetop method of all grain brewing really doesn't allow for higher gravity beers in volume but that's where DME/LME and a bit of dilution comes in handy.

If you're within the "brewer's window" of 145F-155F for an hour or more that's generally good enough to attain efficient conversion. For some beers I will do extended step mashes to get fermentability and dryness but it depends on grist and style.

 

[Soulshine2]

I use an igloo cooler. I measured the temp after mixing the grains and I got 154F, my target temp. However, 45 mins later I decided to take a temp reading and it was at 148F. I have never seen this before. What did I do wrong?

colder ambient temperature ?...maybe you forgot to preheat the mash tun?
I usually pour in about 2/3-3/4 of my intended mash water ,stir well,and check temp , if its low I wait a few minutes to check/wait for the temp to stabilize and pour more ,hotter water in until its 2 degrees higher so during the mash it'll lower into a decent range. If im higher than that I just raise the lid to cool it off and proceed.

 

[urg8rb8]

colder ambient temperature ?...maybe you forgot to preheat the mash tun?
I usually pour in about 2/3-3/4 of my intended mash water ,stir well,and check temp , if its low I wait a few minutes to check/wait for the temp to stabilize and pour more ,hotter water in until its 2 degrees higher so during the mash it'll lower into a decent range. If im higher than that I just raise the lid to cool it off and proceed.

I didn't forget to preheat the may tun, I don't think I preheated enough. It was ambient temperature was colder than usual, so I didn't adjust for it correctly. I'll be more careful next time.

 

[urg8rb8]

I took a final gravity reading and I'm currently at 1.014. I was shooting for 1.016. Since it's only been fermenting for a week, I'm sure gravity will go down a bit more. For sure this lower than expected gravity is due to lower mash temp.

 

[RM-MN]

I took a final gravity reading and I'm currently at 1.014. I was shooting for 1.016. Since it's only been fermenting for a week, I'm sure gravity will go down a bit more. For sure this lower than expected gravity is due to lower mash temp.

Not for sure at all. Yeast has a range of expected attenuation but that is just expectation. It can attenuate far more than expected too...as well as less than expected. That is one reason we suggest taking at least a couple hydrometer readings before bottling to verify that the yeast are done.

The mash temperature matters while conversion is happening and in your case that temperature drop may have happened during the conversion which definitely could have caused you to get a more fermentable wort but we don't know that for sure because the conversion speed depends on how fine the crush of the grain is. For some the crush is so coarse that conversion is still happening at 60 minutes and to get completion requires 90 to 120 minutes. In my case with a very fine milling, conversion is done in about 5 minutes.

 

[kh54s10]

I find a larger range of variance of what final gravity ends up as to the predicted FG. If a recipe or software predicts 1.016, I expect to be somewhere near that number. But the range that I see "near" is something like 1.013 to 1.019. If outside that range, then I might be concerned.

An FG prediction is only that - a prediction. There are multitude of factors that will cause your FG to be higher or lower.

 

[Silver_Is_Money]

I noticed that when I transitioned to full volume (I.E., no-sparge) mashing my cooler conversion mash temperatures became much more stable over time.

 

[urg8rb8]

Not for sure at all. Yeast has a range of expected attenuation but that is just expectation. It can attenuate far more than expected too...as well as less than expected. That is one reason we suggest taking at least a couple hydrometer readings before bottling to verify that the yeast are done.

The mash temperature matters while conversion is happening and in your case that temperature drop may have happened during the conversion which definitely could have caused you to get a more fermentable wort but we don't know that for sure because the conversion speed depends on how fine the crush of the grain is. For some the crush is so coarse that conversion is still happening at 60 minutes and to get completion requires 90 to 120 minutes. In my case with a very fine milling, conversion is done in about 5 minutes.

I try to crush as fine as I can with my Corona Mill. I didn't realize it can take as little as 5 mins to convert.

 

[RM-MN]

I try to crush as fine as I can with my Corona Mill. I didn't realize it can take as little as 5 mins to convert.

Don't cut the mash too short. Even though the conversion is done quickly it still takes time to extract the flavors. I don't recommend a mash shorter than 30 minutes after some tasteless beers.

 

[dmtaylor]

I like 40 minutes. Or 45.

 

[Lefou]

Just to be annoying, my step mashes sometimes go over an 60 minutes plus if I want a highly fermentable wort.
I've done a 90 minute step mash with decoction just for fun. Once.

 

[applescrap]

Have been working my way through Palmer and Zainascheff's Brew Strong podcasts, and one of the common themes is to not get hung up on mash temp - if you are reasonably close then don't worry about it.

Havent seen those, cool, I love listening to palmer. It feels accessible and practical.

 

[SteveH aka shetc]

Havent seen those, cool, I love listening to palmer. It feels accessible and practical.

http://www.thebrewingnetwork.com/shows/brewstrong/

 

[RM-MN]

Just to be annoying, my step mashes sometimes go over an 60 minutes plus if I want a highly fermentable wort.
I've done a 90 minute step mash with decoction just for fun. Once.

It's hard to annoy me much with brewing techniques. However, have you checked to see when the conversion is done? That time is directly related to the crush of the grain and in many cases is complete long before the 90 or even 60 minutes are up.

 

[Lefou]

An iodine tester or refractometer isn't in the brew inventory - yet.
I do the "taste test" for now and rely on time. While the mash is going on I typically get a yeast starter going.

 

[RM-MN]

I bought a pint (smallest bottle they had) of Iodine a few years ago so I could test for conversion. I don't think you could tell that is has any used from it as it only takes a drop to do the test. I went to the wrong store because others have smaller bottles. For instance:

https://www.target.com/p/povidone-i...bYzW1LO14hVBfkYSJw0aAmmXEALw_wcB&gclsrc=aw.ds

https://www.shopmedvet.com/product/...AfT1v07ULPuUTEifD7ZPJtZZPkcinr1EaAojkEALw_wcB

It wasn't very expensive and a real eye opener when I started testing to see how long conversion took with my very finely ground grain.

 

[Lefou]

LOL ... well, that 8oz bottle from the first link will definitely last a while. There are at least half a dozen chain pharmacies within 15 minutes of me but I've been lazy.
I'm STILL waiting on a straw-purchase refractometer that was promised on a side deal with one of the kids. He liked the digital ThermoPen and I've resorted to stealing it back on occasion.

 

[sbsmann]

I just brewed in my garage last week when it was about 25 degrees. I have a 10 gallon Home Depot cooler for my MT. I leave it indoors where I fill it with a few gallons of hot tap water that I run down the sides and lid. I put the lid on it and leave it sit for 5-10 minutes before my mash in.

I leave it indoors until my strike water is ready to go and then I empty my mash tun and take it outside to the cold garage to mash in.

After mashing in and getting the temp correct, I seal it and put two jackets on it. Last week I held 152 for 60 minutes no problem.

 

[urg8rb8]

Not for sure at all. Yeast has a range of expected attenuation but that is just expectation. It can attenuate far more than expected too...as well as less than expected. That is one reason we suggest taking at least a couple hydrometer readings before bottling to verify that the yeast are done.

The mash temperature matters while conversion is happening and in your case that temperature drop may have happened during the conversion which definitely could have caused you to get a more fermentable wort but we don't know that for sure because the conversion speed depends on how fine the crush of the grain is. For some the crush is so coarse that conversion is still happening at 60 minutes and to get completion requires 90 to 120 minutes. In my case with a very fine milling, conversion is done in about 5 minutes.

I just took another gravity reading and it is sitting at around 1.011 - 1.012. Very far from 1.016. Is it for sure from low mash temp now? Luckily this is an IPA.

Do you think I'll notice that it will lack body or maltiness as compared to 1.016?