Overshot mash temperature both times with BIAB - any tips?

[vance]

Done two brews, overshot my mash temp both times and ended up starting in the low 160s instead of having my grain drop it to where I want. Using a propane burner and an 11 gallon kettle. Any suggestions?

 

[JordanKnudson]

Ummmm...don't heat your strike water as high on the next one...are you looking for something more than that?

 

[Sammy86]

With any mash in process you want to start higher then your intended mash temperature. It unfortunately varies by system but many Brewers start 10-12 degrees above and a grain of 72° will generally fall into the intended temperature range.

For my cooler mash tun 11° above mash temp is the money spot...to cool down I would have some ice or cold water on hand...you can also mix it vigorously to get the temp down.

Hope this helps!

 

[vance]

Ummmm...don't heat your strike water as high on the next one...are you looking for something more than that?

Sort of, yeah? Like how much above my mash temperature should I shoot for? I had heard drop it in when the water was in the low 160s, but that might be for three vessel systems where you lose heat pouring the water.

 

[vance]

With any mash in process you want to start higher then your intended mash temperature. It unfortunately varies by system but many Brewers start 10-12 degrees above and a grain of 72° will generally fall into the intended temperature range.

For my cooler mash tun 11° above mash temp is the money spot...to cool down I would have some ice or cold water on hand...you can also mix it vigorously to get the temp down.

Hope this helps!

Hadn't thought of the ice water, I'll keep some nearby next time. Thanks!

 

[JordanKnudson]

Sort of, yeah? Like how much above my mash temperature should I shoot for? I had heard drop it in when the water was in the low 160s, but that might be for three vessel systems where you lose heat pouring the water.

Well, every system is slightly different, so the strike water temperature required to stabilize the mash at a particular temperature is dependent on exactly how your system responds. You can do some very simple trial and error to figure it out. If you ended up too high in your last mash, think about how much you overshot by, and reduce your strike water temp by a similar amount next time, and see if that gets you the desired result. Then you can dial it in super precisely from there on subsequent batches.

 

[oujens]

What calculator are you using? Are you doing a full volume mash and is the calculator set that way too? For my BIAB no sparge setup, an average grain bill requires a strike temp of 159F to get to about 152-153F, so about 6-7F higher than mash temp. Is this about the difference you are noticing with your system?

 

[TexasWine]

No need for trial and error. Use this. You'll be spot on every time.

https://pricelessbrewing.github.io/BiabCalc/

And keep in mind that not just every system will be different, but also every water to grain ratio and every ambient temp your grain is at to begin with. If your grain was sitting outside at 80F you'll get a different answer if it was sitting inside at 70F.

 

[eadavis80]

I always have some ice trays filled if need be. If I'm over a bit, a couple trays worth knocks it down 3-4 degrees and then I'm where I need to be.

 

[vance]

oujens - I used BS2 for my first batch, although my system specifications aren't very dialed in. For the second batch I didn't bother since I was copying straight from the Centennial Blonde recipe.

TexasWine - I looked at that calculator before I did my first brews and couldn't make much sense of it, I'll revisit now that I have a bit of actual experience.

 

[EDF713]

I had a similar issue on my first BIAB batches. I use http://biabcalculator.com, but here is what I've done to fix it.

1. Us the calculator, and make sure you check the grain temp. I brew in the garage and the grain warmed up more than I expected while heating my water.

2. Wait a little while after it looks like your water is heated. I found that after I shut off the propane that the water temp continued to rise.

3. Save some water, ideally ice cold and boiling , to make adjustments after 15 min.

 

[dmtaylor]

With BIAB, I only assume 3-5 degrees F temperature drop, as opposed to when I use a cooler and traditional batch sparge when it loses about 12 degrees F. BIAB is a simpler process, so you don't need to heat up your strike water nearly as much as with other brewing methods.

 

[Morrey]

When you are taking a temp to determine when your strike water is ready for mash in, are you stirring the water rapidly to evenly mix the water in your kettle? With the fire directly at the bottom of your kettle, that layer of water is hotter than the surface. I have a Blichmann with a therm affixed, and I go by that to get close....then stir and measure with a Thermapen. Stirring will give you a better idea of your strike temp.

I used to overshoot before I figured this method, so always have a few ice cubes handy to adjust. If I mash in with my water at 156F, it will drop down to 152F on the money. This is summer time, winter YMMV. Grain temps have an influence if they are cold from being stored in a fridge, or if they are warm from being outside above 72F.

 

[vance]

With BIAB, I only assume 3-5 degrees F temperature drop, as opposed to when I use a cooler and traditional batch sparge when it loses about 12 degrees F. BIAB is a simpler process, so you don't need to heat up your strike water nearly as much as with other brewing methods.

Wouldn't you need to heat it more, since a kettle isn't insulated like a cooler?

 

[TheMadKing]

It took me a couple of batches to dial in my temp drop in BeerSmith, but I usually mash with 7.1 gallons of water, and a typical 1.05 OG beer mashed at 152 will have a strike temp of 158 in my system. Because you're doing a full volume mash, the larger mass of water compared to the grain results in much less temperature drop than a standard all-grain system. Priceless brewing calculator works well, and if you tinker with the BeerSmith settings you can dial it in pretty well too.

 

[TheMadKing]

Wouldn't you need to heat it more, since a kettle isn't insulated like a cooler?

No, for 2 reasons

rate of heat loss is independent of initial strike temp in regards to mash temp.

Meaning that if you want to mash at 152, it's better to start at 152 and cool to 148, than it is to start at 156 and hit 152 by the end. This is because of the fact most of the conversion happens in the first 15-20 minutes of the mash, so it's much better to start at the correct temperature than it is to try to account for the higher rate of heat loss. I also have a jacket on my kettle so my heat loss is minimal (3 degrees or so over an hour).

The second reason is what I said above about having a larger mass of water. You will cool it less when you add the grain.

 

[dmtaylor]

Wouldn't you need to heat it more, since a kettle isn't insulated like a cooler?

Great question. Actually if I want to mash at 152 F (for example), I would typically aim for about 155 F then let it fall to the 140s over the course of the mash. In fact I do this all the time, been doing so for years. In my view, the average mash temperature over the full extent of the mash is all that really matters -- I really don't care at all whatsoever about maintaining absolute constant temperature the whole time, because 1) it's impossible and 2) it doesn't make any discernible difference in the quality of the final beer! Experiments could be run on this, but with a conservative P value like 0.05, I'm sure I already know what the outcome would be, same as anything else... "we were unable to reliably determine any difference..." yadda yadda.

 

[TheMadKing]

Great question. Actually if I want to mash at 152 F (for example), I would typically aim for about 155 F then let it fall to the 140s over the course of the mash. In fact I do this all the time, been doing so for years. In my view, the average mash temperature over the full extent of the mash is all that really matters -- I really don't care at all whatsoever about maintaining absolute constant temperature the whole time, because 1) it's impossible and 2) it doesn't make any discernible difference in the quality of the final beer! Experiments could be run on this, but with a conservative P value like 0.05, I'm sure I already know what the outcome would be, same as anything else... "we were unable to reliably determine any difference..." yadda yadda.

I disagree with this reasoning because of my above post, but I bet we both make good beer.

I am basing my assertions off of brukaisers research on mash temperatures and conversions rates.

It doesn't make sense that the average mash temperature would be as important for conversion as the initial mash temperature since it's an exponential decay (decreasing returns) as far as conversion rate goes.

 

[dmtaylor]

most of the conversion happens in the first 15-20 minutes of the mash

For whatever it's worth (2 cents), I agree with the above...

so it's much better to start at the correct temperature than it is to try to account for the higher rate of heat loss

But I disagree with this. Your method will result in a lower average mash temperature and thus give you a (very slightly) drier beer / more fermentable wort than you'd planned.

having a larger mass of water... will cool it less when you add the grain.

That's a fact I totally agree with.

 

[dmtaylor]

I disagree with this reasoning because of my above post, but I bet we both make good beer.

Now that I am very sure of!

I'll admit I could be wrong. However I'll also admit that you and the Kai-ster could also be wrong.

 

[Morrey]

No, for 2 reasons

rate of heat loss is independent of initial strike temp in regards to mash temp.

Meaning that if you want to mash at 152, it's better to start at 152 and cool to 148, than it is to start at 156 and hit 152 by the end. This is because of the fact most of the conversion happens in the first 15-20 minutes of the mash, so it's much better to start at the correct temperature than it is to try to account for the higher rate of heat loss. I also have a jacket on my kettle so my heat loss is minimal (3 degrees or so over an hour).

The second reason is what I said above about having a larger mass of water. You will cool it less when you add the grain.

Great point you made about timing of conversion during the mash. The "critical" time of conversion is at and near the beginning of the mash in cycle. I did an iodine test on my last mash, and at the 20 minute point of mash in, I had converted. I let it ride on out for 40 more minute to ensure flavors were fully extracted and enzymes worked, but the first 20 minutes is when you get a critical part of job done. I wrap with a blanket to insulate, and am especially mindful of the strike temps at the first of the mash in cycle for single infusion BIAB.

If my target temp is 152F, only experience with my system will tell me how much drop to allow. I always go to 156 and it falls right in at 152. Kentucky windage concept, but I have done this enough to know my variables. When I mash in, dropping to 152F is critical to me for consistency reasons.

 

[Soyben]

+1 on using the pricelessbiab calculator.

I stick a thermometer in my bag of crushed grain the night before so I know the grain temp. I get it milled at the LHBS and they put it in a paper bag, I just poke my thermometer through the bag.

I tend to over shoot my target strike temp by a couple of degrees and stir well. With the pot uncovered and stirring the temp comes down in just few minutes and is pretty stable, this helps eliminate hot spots.

I use a polder temperture probe that I have water proofed with heat shrink tubing to monitor the temp.