Author Topic: Specialty grain mash converted?  (Read 3019 times)

Offline gigatropolis

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Specialty grain mash converted?
« on: May 26, 2011, 10:33:25 PM »
Did my first mash for a partial mash batch in my new igloo cooler mashtun, but didn't use any base grains. The mash was a lot of biscuit, aromatic, some Vienna, and a bunch of crystal. boiled with 6# pale LME and 1# Minich LME and put into fermenter with OG at 1.070.
On the fifth day all was quiet for about 24 hours so took a gravity reading and it was at 1.030...hmm Stirred it up, added an ounce of Amarillo, and put it back in the closet.

  So my concern is: Was there enough enzymes in the specialty grains to fully convert all the sugar? Maybe it won't go any lower because nothing left but starch.

  What would the beer taste like if it had a lot of starches left? Tastes a bit sweet but nothing too out of the ordinary.

  Mashed for about 1:20h at 149

  Thanks,

 
 

Offline thomasbarnes

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Re: Specialty grain mash converted?
« Reply #1 on: May 27, 2011, 04:16:29 AM »
On the fifth day all was quiet for about 24 hours so took a gravity reading and it was at 1.030...hmm Stirred it up, added an ounce of Amarillo, and put it back in the closet.

Ouch. You shouldn't have stirred, unless you did so really carefully. Stirring after fermentation starts is a good way to oxidize your beer.

So my concern is: Was there enough enzymes in the specialty grains to fully convert all the sugar? Maybe it won't go any lower because nothing left but starch.

Possibly. You had a whole bunch of specialty grains, which are pretty much diastatically dead, plus some Vienna which had just enough enzymes to convert itself with a bit left over. Depending on the proportion of Vienna malt you could easily have had incomplete conversion. OTOH, you mashed for a fairly long time, so you might have gotten full conversion. Without knowing the proportion of crystal and aromatic malts to Vienna malt, you can't know for sure.

Good information on diastatic power here:

  http://www.beersmith.com/blog/2010/01/04/diastatic-power-and-mashing-your-beer/

All that said, I wouldn't worry about it too much. I'm guessing that your mini-mash formed about 20-30% of the total grist. Since LME is usually highly fermentable and the Munich LME will ferment reasonably well, it will probably all balance out.

If not, next time add some diastatically powerful malt (e.g., Pils or American pale) to get full conversion and back down on the specialty malts. Also, no need to mash crystal malt; just add it to the mash before mash out.

I think that your current problem isn't related to mashing, though. I think you're just seeing incomplete fermentation, which should clear up with time. Assuming you're using an ale yeast, it's not unreasonable for a bigger beer to take a couple of weeks to finish fermenting. If you haven't hit your expected FG after a couple of weeks, then it's time to start worrying.

What would the beer taste like if it had a lot of starches left? Tastes a bit sweet but nothing too out of the ordinary.

Dextrin malts will make a beer seem really full-bodied and chewy - like a doppelbock or English barleywine - and your FG will be a bit higher than if you had a more attenuable wort. Excess starches in the beer might also give it a haze. Underattenuated beer will taste sweet, possibly even cloyingly so, but if it's just unfermented simple sugars in the wort, eventually the yeast will eat them and you'll get your expected FG.
« Last Edit: May 27, 2011, 04:18:08 AM by thomasbarnes »

Offline gigatropolis

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Re: Specialty grain mash converted?
« Reply #2 on: May 29, 2011, 09:56:25 AM »
Thanks for the replies,

  Calculated the mash to have conversion power of 31.4 lintner which is somewhat close to the 35 needed to be self converting. I forgot to mention there was 1# of Victory that may have hellped a lot.

Offline jeffy

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Re: Specialty grain mash converted?
« Reply #3 on: May 29, 2011, 11:02:16 AM »
Thanks for the replies,

  Calculated the mash to have conversion power of 31.4 lintner which is somewhat close to the 35 needed to be self converting. I forgot to mention there was 1# of Victory that may have hellped a lot.


But this really doesn't make any difference in your instance.  You achieved an original gravity of 1.070, which means you extracted at least some if not all the sugars from your grist.   Your issue is that your fermentation isn't finished yet.  You tested the fermenting wort at 1.030, which will of course taste sweet.  I'm not sure why you think that this gravity reading would be at all related to the amount of sugars you expected to get out of the steep.  It either needs more time or more yeast or perhaps you didn't get enough oxygen into it initially for the yeast to prosper. 
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Offline a10t2

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Re: Specialty grain mash converted?
« Reply #4 on: May 29, 2011, 11:56:49 AM »
It either needs more time or more yeast or perhaps you didn't get enough oxygen into it initially for the yeast to prosper.

I don't think you can draw that conclusion from what gigatropolis has said. The high FG could very well be due to unconverted starches from the mash.

Even if the DP was high enough for conversion, you may not have given it enough time, or the temperature or pH could have been a little out of line and kept it from converting.
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Offline jeffy

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Re: Specialty grain mash converted?
« Reply #5 on: May 29, 2011, 01:47:54 PM »
It either needs more time or more yeast or perhaps you didn't get enough oxygen into it initially for the yeast to prosper.

I don't think you can draw that conclusion from what gigatropolis has said. The high FG could very well be due to unconverted starches from the mash.

Even if the DP was high enough for conversion, you may not have given it enough time, or the temperature or pH could have been a little out of line and kept it from converting.
The conversion took place as far as I can see.  He has 7 pounds of LME in five gallons and an OG of 1.070, so some if not all of his specialty malts must have contributed some sugars as well as flavors.  His final gravity (or at least the preliminary reading that he took) is high and sweet from unfermented sugars, thus my comment/opinion on the fermentation activity.
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Offline a10t2

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Re: Specialty grain mash converted?
« Reply #6 on: May 29, 2011, 05:00:25 PM »
He has 7 pounds of LME in five gallons and an OG of 1.070, so some if not all of his specialty malts must have contributed some sugars as well as flavors.

The OG just indicates that the grains contributed *something* - a gravity reading alone can't tell us whether that something is starch or sugar or both.
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Offline jeffy

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Re: Specialty grain mash converted?
« Reply #7 on: May 29, 2011, 07:33:26 PM »
He has 7 pounds of LME in five gallons and an OG of 1.070, so some if not all of his specialty malts must have contributed some sugars as well as flavors.

The OG just indicates that the grains contributed *something* - a gravity reading alone can't tell us whether that something is starch or sugar or both.
I'm not sure where you're going with this.  Hydrometer readings are a measure of sugar in solution not starch. 
Regardless, his second reading is high and that wort tastes sweet.  To me this means that it has not finished fermentation. 
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Re: Specialty grain mash converted?
« Reply #8 on: May 29, 2011, 08:02:40 PM »
I'm not sure where you're going with this.  Hydrometer readings are a measure of sugar in solution not starch. 
Regardless, his second reading is high and that wort tastes sweet.  To me this means that it has not finished fermentation.

You may be right. I was just pointing out that either sugar or starch would increase the SG, so a hydrometer reading alone can't tell us which it is.
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Offline thomasbarnes

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Re: Specialty grain mash converted?
« Reply #9 on: May 29, 2011, 09:13:20 PM »
I'm not sure where you're going with this.  Hydrometer readings are a measure of sugar in solution not starch. 
Regardless, his second reading is high and that wort tastes sweet.  To me this means that it has not finished fermentation. 

While I agree that the problem is probably incomplete fermentation, hydrometer readings measure all dissolved or suspended stuff in liquid, not just sugar. If it's got a density heavier than water, it will make SG read higher. If it's got an SG lower than water, it will make SG read lower, it doesn't matter if it is/isn't sugar/alcohol.

Offline thomasbarnes

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Re: Specialty grain mash converted?
« Reply #10 on: May 29, 2011, 09:23:18 PM »
Calculated the mash to have conversion power of 31.4 lintner which is somewhat close to the 35 needed to be self converting. I forgot to mention there was 1# of Victory that may have hellped a lot.

Given the generous mash time, you probably got full conversion. 1 lb. of Victory would have helped a lot, since it has DP 50 and was probably the most diastatically powerful grain in the mash. Assuming your Vienna converted itself and perhaps 15% more, and your Victory malt converted itself plus 70% more, you probably got close enough to full conversion.

I didn't mention this before, since I didn't want to sound too critical, but why did you add all sorts of crystal malts if you intended to break down the dextrins in the crystal malt by mashing it? It seems simpler to use less specialty malt and more DME or base malt.

The lessons for next time are to back down on the specialty malts or add a bit of diastatically powerful base malt, and, possibly, do a starch conversion test.

Offline gigatropolis

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Re: Specialty grain mash converted?
« Reply #11 on: May 30, 2011, 08:11:33 AM »
Calculated the mash to have conversion power of 31.4 lintner which is somewhat close to the 35 needed to be self converting. I forgot to mention there was 1# of Victory that may have hellped a lot.

Given the generous mash time, you probably got full conversion. 1 lb. of Victory would have helped a lot, since it has DP 50 and was probably the most diastatically powerful grain in the mash. Assuming your Vienna converted itself and perhaps 15% more, and your Victory malt converted itself plus 70% more, you probably got close enough to full conversion.

I didn't mention this before, since I didn't want to sound too critical, but why did you add all sorts of crystal malts if you intended to break down the dextrins in the crystal malt by mashing it? It seems simpler to use less specialty malt and more DME or base malt.

The lessons for next time are to back down on the specialty malts or add a bit of diastatically powerful base malt, and, possibly, do a starch conversion test.

 I'm lucky to have learned a lot from this batch and will will things better from advise you guys gave me.
 The crystal malts were in the mash simply because they were part of the recipe, and I didn't bother to include these grains in the diastatic calculations. My next mash will definetly include a few pounds of over powered base malt so there is no worries about the enzymes.
Making a high gravity beer with using a "real" mash ton and lots of specialty grains for the first time, there is probably a slue of reasons the yeast fizzled out at 1.030. I think the low diastatical power played a role with this and hope the beer will ferment down a little more to at least 1.024 by next week. Anyway, the beer tasted awesome after the first week even though it was sweeter than most beers I like. It will be enjoyed :)

  Thanks,
 

Offline Will's Swill

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Re: Specialty grain mash converted?
« Reply #12 on: May 30, 2011, 10:13:46 AM »

I didn't mention this before, since I didn't want to sound too critical, but why did you add all sorts of crystal malts if you intended to break down the dextrins in the crystal malt by mashing it? It seems simpler to use less specialty malt and more DME or base malt.


You lost me with this one.  I typically throw crystal malt in with my mash (when the recipe calls for it, of course).  Is this not standard practice?  Are you suggesting using the crystal some other way?
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Offline dmtaylor

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Re: Specialty grain mash converted?
« Reply #13 on: May 30, 2011, 01:27:52 PM »
I could be wrong, but I believe aromatic malt has some enzymes, and Vienna definitely has plenty, and this was only a partial mash... so why should we be very surprised that this converted?  At 80 minutes, it was definitely mashed long enough to give those enzymes time to work.

Five days isn't much time to expect fermentation to be complete.  Warm it up and give it more time -- you might be pleasantly surprised that the gravity falls a few more points.  Maybe no lower than 1.022 with all the extract and crystal you've got in there, but this is more likely a result of bad extract than a bad mash... perhaps some combination of the two effects, but my wager is on the extract and crystal being the more limiting factors.
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Offline gigatropolis

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Re: Specialty grain mash converted?
« Reply #14 on: May 31, 2011, 10:21:51 PM »
I could be wrong, but I believe aromatic malt has some enzymes, and Vienna definitely has plenty, and this was only a partial mash... so why should we be very surprised that this converted?  At 80 minutes, it was definitely mashed long enough to give those enzymes time to work.

Five days isn't much time to expect fermentation to be complete.  Warm it up and give it more time -- you might be pleasantly surprised that the gravity falls a few more points.  Maybe no lower than 1.022 with all the extract and crystal you've got in there, but this is more likely a result of bad extract than a bad mash... perhaps some combination of the two effects, but my wager is on the extract and crystal being the more limiting factors.


  After another 5 days at 71 degrees, I took a gravity reading and it was still right at 1.030; so I think this bad boy is done fermenting. Aromatic is at 6 L and there was a full pound in the mash, which probably was the main reason if it didn't convert as much as was desired.Wife likes the beer a lot so nothing is more important anyway.
  also noticed a lot of heat escaped during the mash at the bottom of the cooler because of the metal valve so will need to find a way to insulate that next time. Anyway, the beer is now racked into the secondary with a fresh ounce of Amarillo were it can hang out for another week before the joys of bottling.