Mash temperatures and yield

[lxwitt]

I'm getting real close to perfecting my all grain procedure; however, there's one thing I can't quite nail down.

So I see a lot about mashing at different temperatures will yield different amount of ferment able sugars. My next goal is an espresso oatmeal milk stout using 11 pounds 2 row and .65 each of roasted barley and chocolate.

Here's my problem. I realize mashing at 149 will give you the highest fermentable yield, but takes longer. Mashing at 158 will give you a heavier body and that will occur at a lower time.

So here's my question. What is a good time table (I guess is the word) that I can get a good balance between a desirable OG (I'm shooting for 1.062) but with a good body.

Long story short, if I have 11 pounds 2 row, and I mash it at 149 for 90 minutes (like Charles Papazian says) and I take that same 11 pounds but mash it at 158 for 20 minutes. (Also according to Charlie) what would be the difference in the OG? I also found somewhere else on the internet that if I mash at 149 for 20 minutes, then 158 for 40 minutes is a good balance between good OG and good body. Is this a mash schedule you would use?

 

[iijakii]

The OG shouldn't vary by much. The difference you'll see is in fermentability and how low the final gravity gets.

If you're wanting it dry do 148
If you want it middle-road do 152
If you want it fuller body go 156

Wiggle room in all things, and you might find it doesn't make THAT much of a difference.

 

[lxwitt]

So what about the 148 for 20 and 158 for 40? Is that enough time to convert the sugars at the lower temperature? Or should I do 30/30, 40/30 etc.?

 

[iijakii]

I don't have any personal experience with doing a small step mash like that. Also don't really see the point.

But to your question on time length, 60mins at any temp between 148-158 will be fine for conversion. Some people like to mash for 90mins when they go down into the 140s, but I've never seen an issue with 148 mash temps and conversions at all.

 

[Homercidal]

First, I'm not sure how accurate the difference in temperature makes in actual body. In my experience it's fairly minimal. The biggest cause of more "body" in beer, from my experience, has been from using more grain, or using more grain that doesn't ferment well.

Your mileage may vary.

Also, I'm not sure mash temp even affects OG as much as Mash time. At some point you are going to get complete conversion. That means all the starches that can convert to sugars will, and there isn't much to do beyond that. You will also get about the same OG on both ends of the temp range, as both of them are helping to create sugars, just some sugars will be short-chain sugars, and some will be Long-chain sugars.

Time may play into it. Your OG is affected by the amount of sugars, and if your pH is off by enough, you *might* not get full conversion in a certain amount of time (although I believe we are taught to mash for 60 minutes just to be sure. 90 minutes seems like PLENTY.)

Bottom line: Mashing at a low temp might give you a more fermentable wort, but not necessarily a higher OG. It's just that the sugars are more able to be fermented so more of the OG is converted to alcohol when compared to a higher mash temp.

Unless your pH is way off a 90 minute mash is plenty to convert all of the starches (AFAIK). if the pH was off enough and you tried to do a 20 minute mash, then you might not get full conversion. All of this is variable and I'm just throwing what-ifs out there.

I'm curious to see what others have to say on this. The best thing would be to read up on the calculations and do a bit of math, or to find a calculator and see what their predictions give you. I use beersmith, mostly.

 

[lxwitt]

Thanks for the info.

Personally I do like the least amount of times that I have to open my MT and possibly increase the margin of error with additiona infusion temps and stuff.

 

[dmtaylor]

I think playing with time as a factor and not just temperature is a good idea. Personally over the past 10 years I have mashed almost every beer for just 40 minutes at about 150 F. This was based on experimentation at the time, where I determined that 40 minutes was plenty at 150 F. I'm getting to the point now of renewing my interest in this area. Perhaps I really could be mashing at more like 155 F for just 20 minutes, and save some more time on brewing day. Need to experiment more with this.

 

[m00ps]

you can mash lower than 149 and still get good conversion....

I think if you want a beer to be dry and have body you should be looking more at your grain bill selections. Add some flaked wheat or rye or something, pick a yeast strain that can leave a silky mouthfeel

I posted this in a similar thread of general mash guideliens
This is my rule of thumb

146-148: very dry (saisons)
148-150: dry (Dubbels, Tripels, Wits, IPAs)
151-152: normal (Pale Ales, Hefes, Amber Ales, any lagers)
153-154: moderate body (Brown Ales, Porters)
155: full body (stouts)

I have been successful with just doing a 60min single rest followed by a 10min mashout at 168 for everything. If im brewing a hefe or feeling adventurous with a saison ill try a ferulic acid rest or protein rest to get the specific compounds the yeast will react to, but thats not too often

 

[lxwitt]

Based off research that I've done, this topic definitely sounded a lot more complicated. But based off what I've been told on here it's not. Previous brews I've done in the past came out with really low OG's so I figured my mash procedure was where I was going wrong.

 

[dmtaylor]

The biggest factors for hitting desired gravity have absolutely nothing to do with mash time or temperature. You should be concerned with how hard you're crushing/milling the grains, and ensure mash pH is from 5.2 to 5.5. Crush hard, mash at the right pH for a reasonable amount of time and temperature, and sparge well, and your efficiency should hit about 70% or more without much trouble at all. You've been having trouble with OG? Yeah, don't worry about mash time or temperature, that's a very minor factor. Crush harder, that's the biggie.

 

[iijakii]

Based off research that I've done, this topic definitely sounded a lot more complicated. But based off what I've been told on here it's not. Previous brews I've done in the past came out with really low OG's so I figured my mash procedure was where I was going wrong.

There are a lot of factors, but temperature isn't one as long as you're within the range.

The most common is your crush. Do your grains look pretty milled or are there a lot of whole kernels in-tact etc? Besides that, what's your general mash technique like. IE: how do you sparge, are you commonly winding up with more liquid than you planned etc. And I'm assuming you're using a good program like Beersmith to calculate your recipes and are using an appropriate amount of grain.

 

[lxwitt]

The milling is another thing I'm experimenting on. I went as tight as i could and then stuck the runoff. I've heard .37 is a good width.

 

[lxwitt]

The first few times I tried all grain I was mashing at 158. Don't ask me where I got that number but now I realize that was probably too high. But single infusion, fly sparging. Early on I omitted the mash out before I was aware that it actually helped loosen sugars from the grain allowing them to sparge better. That's another thing I have learned.

Like I said I'm sooooo close to perfecting my process. I do use beersmith and i feel like I got my equipment profiles dialed so I get the right volume. I recently got my own mill and have been messing around with that. My most recent batch I milled as tight as I could. .025. I ended up sticking the runoff so I think that's too tight. I heard .037 or the thickness of a credit card is a good number.

 

[brewmeister13]

If you are only shooting a few points low (2-6), I'd actually say it is probably BeerSmith and the way you take measurements. A fundamental "law" of brewing is that post mash/pre-boil you will never have more or less sugars (unless you add them) than you started with. If you run numbers from BeerSmith, this law seems to be broken.

I'll use a recent batch as an example. I brewed an IPA with a desired OG of 1.064 and 6 gallon batch size. To achieve this BeerSmith tells me to hit a pre boil of 1.054 and 8.12 gallons. It then tells me I should end up with an OG of 1.064 and 7.21 gallons in my BK before transfer. Since sugar is neither created or destroyed Preboil SG X Preboil volume=Postboil SG X Postboil volume. To run these numbers I multiply SG X 100 to get Gravity Points (GP). If this is confusing, Daniels does a much better job of explaining this than I. Anyways, after running the numbers you get Preboil=438.48 and Postboil=461.44. This makes it seem like sugar has magically appeared in my BK. Since that isn't possible, I've actually just undershot my gravity.

So what's going on? The culprit is thermal expansion. BeerSmith makes the assumption that you are taking you Preboil Volume at boiling temperatures. It is also using room temperature volume for Post boil. Water/wort expands about 4% from room temp to boiling. So if you are taking your Preboil Volume at mash temps or lower you have an error. Once this is accounted for the numbers are just about the same (but still a little low).

That's probably the longest winded answer for, hey, check your pre boil volume right before boil or correct for expansion that you've ever gotten.

 

[ba-brewer]

I had similar questions/thoughts about why people say the OG is not effected by the mash temp. There is only so much starch and alpha/beta enzymes can only break the starch chains down so far by themselves. It seems like the OG should peak at a temp where both alpha and beta enzymes are equally active and fall off as the temp moves up or down from that optimally temp.

I think the reason people do not see any difference is because it is common practice to reduce the max grain sugar extraction/conversion to 80 to 85% of the total published potential sugars, so any OC difference caused by mash temp gets lost in that fudge factor.

I use beersmith for all of my brewing and generally like it, but one thing I dont like or really dont get is why they base so much of the calculations off the brewhouse efficiency. To me brewhouse efficiency should be a calculated value based on the mash and lauter efficiency and other brewing related losses. If you want to really get your beersmith system dialed in you need to use a spreadsheet or calculator to get the estimated first running gravity to come up with your conversion efficiency then fiddle with the brewhouse efficiency until they match.

There is good information here regarding efficiency and for estimating your first running.
http://braukaiser.com/wiki/index.php?title=Understanding_Efficiency#Conversion_efficiency

This parti gyle calculator is helpful for calculating sparge runnings if you batch sparge.
http://braukaiser.com/wiki/index.php?title=Batch_Sparge_and_Party_Gyle_Simulator