Mash Temp and Flavor

[^Tony^]

My latest obsession is learning more about mash temp and flavor impact. Specifically, BIAB method.

I used a new kettle and new burner for my last batch of IPA. The wind blew out the burner during the infusion mash and I did not notice until the thermometer reached 144f at 30 minutes, then I ended up over heating it to 168f (I blame the dog rolling in bird crap for this one ) trying to bring it back up a bit. I ended at 150f at the end of the infusion and thought, not a perfect day but 150f is pretty good so let's see what happens. (And no, I did not do an iodine test. I used to but got my process down with my last kettle and burner so I knew how to control the infusion temps...it never occurred to me that I would have such a different experience with the new gear.) The wort at pitch tasted like it usually does. First FG sample test was sweeter than I expected but in a good way with a ton of great hoppiness. At bottling my ABV was about 1% too low and the FG was about 0.003 higher than it should have been but so balanced with the IPA style of my hop additions that I ended up with one of the best IPA's I have ever made. Starts off fruity and sweet and ends with a smooth subtle bitterness. Clean and crushable.

I know there is a bunch of info on Brulosophy et. al. but I want some more personal experiences. Pro's and more have the gear to control this stuff and I have just made do with what I had as I slowly add to my fancy gear inventory. I have read a bunch about mash temp and learned a lot by experience. But, like so much in academia, what's in a book is usually the "ideal" and I am interesting in some of your personal experiences and learning so I can try to - and pardon the expression - flatten the "learning" curve a bit.

I want to hear your mistakes and success. Did you ever brew 1 batch and mash too low, then brew the same recipe and mash too high? How did the flavor change?

Please share with me!

 

[Bubba Wade]

I usually shoot for 150 to 152, but end up sometime at 156 or at 147. But there doesn't seem to be much difference to me in body or in fermentability in that range. On the other hand, I usually just judge the batch by whether it tastes good.

 

[^Tony^]

I usually shoot for 150 to 152, but end up sometime at 156 or at 147. But there doesn't seem to be much difference to me in body or in fermentability in that range. On the other hand, I usually just judge the batch by whether it tastes good.

True words. I try not to worry too much about temp if I can keep it in the 145-155 range...hence my lack of iodine testing. For this one, I'm thinking having the less fermentable wort, hence the sweetness, was from when I over heated it and the higher mash temp just didn't break down the proteins as much as it should have. Less fermentable sugars = sweeter wort/beer and higher FG. Totally not what I was trying to do but then again, sometimes chance is just as good as skill.

I think I got lottery style lucky and I will have to brew this recipe 5 more times to figure it out....I will just have to suffer through it.

 

[HighVoltageMan!]

Once you hit 168F and try to bring back down, the beta enzymes have been denatured. So that would explain the higher finishing gravity.

I have 3 different mashing temperatures. For German beers and American lagers I mash at 144-145F. I used to do it for an hour but then realized my beers weren't really attenuating like they should and the they were a little sweet. So I have a rule of thumb I use and it helps a lot for attenuation. If I mash low (144-15) go slow, 90 minutes at least, then a 15 minute rest at 158F and another at 168F.

For IPA's and Pale Ale's I mash at 150F for 60 minutes and step to 160F for 15 minutes and another step at 168F to keep them from getting too dry. The second and third steps bring up the gravity and helps with better overall conversion. Some say it helps head retention, but I can't say for sure.

If I want a big malty, slightly sweet beer mash at 154-156f for a hour and go straight to 168F for 15 minutes.

The other thing that makes a big difference is malt flavor is yeast type and healthy fermentation. Some yeast almost always seem to finish a tad sweet (i.e. WLP833) and others seem dry even when the finish gravity is higher (i.e. WLP007). Certain yeasts respond to the different mashes more than others, at least to me. 34/70- WLP830- Wyeast 2124 all are capable of being slightly sweet or dry depending on the mash temperature. Sometimes, the maltiness can come across as sweet.

I think mash temps can have an impact, but sometimes it doesn't seem to make a very big impact in the final beer.

 

[BOB357]

I went with an electric all in one system a couple of years ago, so don't have a problem maintaining mash temperature any more. Prior to that I did BIAB, used a propane burner and brewed outdoors. When the weather was cold and/or it was windy, I had some problem maintaining mash temperature. More often than not, I ended up hitting the numbers, but it required closely monitoring the temperature and being careful not to overshoot when I needed to apply heat after losing a few degrees.

Normally the higher end of conversion temperature range means a less fermentable wort and the lower end a more fermentable wort, though conversion takes longer at the lower end. As long as conversion is complete OG won't be affected much by mash temperature, but FG will due to wort fermentability. When the mash temperature fluctuates, rather than remaining steady, wort fermentability isn't that easy to estimate. The more unstable it is, the less predictable your results will be.

If you want predictability you'll need to keep the temperature stable. Insulating your kettle well is the most cost effective way to do that when using a propane burner..

 

[^Tony^]

Once you hit 168F and try to bring back down, the beta enzymes have been denatured. So that would explain the higher finishing gravity.

I have 3 different mashing temperatures. For German beers and American lagers I mash at 144-145F. I used to do it for an hour but then realized my beers weren't really attenuating like they should and the they were a little sweet. So I have a rule of thumb I use and it helps a lot for attenuation. If I mash low (144-15) go slow, 90 minutes at least, then a 15 minute rest at 158F and another at 168F.

For IPA's and Pale Ale's I mash at 150F for 60 minutes and step to 160F for 15 minutes and another step at 168F to keep them from getting too dry. The second and third steps bring up the gravity and helps with better overall conversion. Some say it helps head retention, but I can't say for sure.

If I want a big malty, slightly sweet beer mash at 154-156f for a hour and go straight to 168F for 15 minutes.

The other thing that makes a big difference is malt flavor is yeast type and healthy fermentation. Some yeast almost always seem to finish a tad sweet (i.e. WLP833) and others seem dry even when the finish gravity is higher (i.e. WLP007). Certain yeasts respond to the different mashes more than others, at least to me. 34/70- WLP830- Wyeast 2124 all are capable of being slightly sweet or dry depending on the mash temperature. Sometimes, the maltiness can come across as sweet.

I think mash temps can have an impact, but sometimes it doesn't seem to make a very big impact in the final beer.

And awesome info. Thank you. This is exactly the kind of information I was hoping to find.
I did think of the yeast. I used S-05 for this batch, which I have used many many times before. I find it typically ferments out clean unless the fermentation temp is way out of control. It was a steady 21c right up to the my A/C cold crash for a week for this batch.

 

[^Tony^]

I went with an electric all in one system a couple of years ago, so don't have a problem maintaining mash temperature any more. Prior to that I did BIAB, used a propane burner and brewed outdoors. When the weather was cold and/or it was windy, I had some problem maintaining mash temperature. More often than not, I ended up hitting the numbers, but it required closely monitoring the temperature and being careful not to overshoot when I needed to apply heat after losing a few degrees.

Normally the higher end of conversion temperature range means a less fermentable wort and the lower end a more fermentable wort, though conversion takes longer at the lower end. As long as conversion is complete OG won't be affected much by mash temperature, but FG will due to wort fermentability. When the mash temperature fluctuates, rather than remaining steady, wort fermentability isn't that easy to estimate. The more unstable it is, the less predictable your results will be.

If you want predictability you'll need to keep the temperature stable. Insulating your kettle well is the most cost effective way to do that when using a propane burner..

Exactly how I do it. BIAB in the back yard. I use a nice thick sleeping bag around the kettle (with the burner turned OFF) to help keep the temp and that works most of the time. I think the wind (and my stinky dog) was the brew wrecker this time.

 

[Mark Farrall]

I've got two common mash approaches 67C/152F for 60 minutes for beers that can tolerate a bit of body. I don't really get any sweetness from these based on the mash, more that the mash doesn't get in the way of the malts. I do 90 minutes at 64C/147F for the pale beers I want to feel dry. A fair few of these will have a step mash for unmalted wheat or spelt (generally just a low start for 15 minutes then a slow ramp to 64C).

So if I really want to dry it out I change the temp, but I feel like the longer mash is just as important. And when I'm doing the longer mash I'm completely happy to leave it longer to let the beta amalyse do it's job completely.

I also do 70C/158F for some sours where I want to leave unfermentable maltose for the Brett. I'm planning to use this approach for a sweet lacto sour where I want the body left in the beer and the ABV pretty low. With this high mash I don't have any problem hitting the numbers, but it's pretty obvious that the sacch can't ferment it as well as predicted.