How do I know what the mashing is done

[Clementine]

I'm just playing with doing an all grain batch. As a practice without risking wasting time and money on a whole batch. I mashed 2lb of pale on the stove, just to understand more about the processes. Although I successively made 3 liters of wort that I canned for using as yeast food on my yeast farm, I guess it was sugar as the yeast ate it happily.

Although I could not set up a decent grain bed filter with how I was doing it. The wort was very cloudy. I boiled it thinking that this was protein that would clear with the hot break. It didn't, I thought it would then clear when I put it in the fridge it didn't. When I canned it then it formed a hot break and cleared when hot. Once cooled it became slightly cloudy but not extremely so like before.

So is that protein in the wort or is it starch that is un-converted?

So is there some way to tell when all starch turned to sugar?

Clem

 

[jgln]

Do an iodine test. Take some wort and add some iodine, just some drops of each, if the iodine turns blue/purple/black it still has not completly converted. If there is no change to iodine color you are done. You can search here or on internet.

 

[jeffjm]

The suggestion about an iodine test is a good one - just be careful the iodine doesn't come in contact with anything you're going to eat or drink.

 

[phenry]

I've never bothered with an iodine test in any of my batches. If I want more fermentable sugars, I mash closer to 149*F and about 90 minutes. If I just want a "normal" beer, I mash around 154*F for 60 minutes.

Brewing really is only as complicated as you make it.

 

[jetmac]

I've never bothered with an iodine test in any of my batches. If I want more fermentable sugars, I mash closer to 149*F and about 90 minutes. If I just want a "normal" beer, I mash around 154*F for 60 minutes.

Brewing really is only as complicated as you make it.

You could also say "brewing better beer requires knowing more of what your beer is doing during your process." Sure you can make great beer, but if you want to make better beer you need to know more about what's happening.

You could be wasting time mashing for 90 @ 149F if the conversion was complete at 70min or sooner. The conversion may not even be complete at that temp for that time. How do you know? You may not care to know but Clementine does. A simple way to know is with an iodine test.

 

[Clementine]

Thanks Hbters, so with iodine is that detecting starch or protein? When i threw some iodine down the sink the other day parts of the sink turned purple (that were dirty).

Also can you use iodopher as the source of iodine?

Jetmac, your right if i can use science to better understand my beer i try to.

Phenry, when the rubber hits the road theory flies out the window and it is nice to know what works for you.

I have to make some more yeast food, im going to take some samples every 5 minutes and it test them. If a camera is handy i post it

Clem

 

[jeffjm]

The iodine is reacting with starch. You can verify that by putting a few drops on a slice of uncooked potato.

I don't know why iodophor wouldn't work. I've been using surgical scrub, which I doubt is much different.

 

[jetmac]

Check out this write up from brau kaiser

 

[shafferpilot]

a bottle of iodine tincture costs about 2 bucks at any drug store... And its reaction to starch in an incomplete mash is undeniable. Instantly swirls black and purple on contact. If you only see a little black, look to see if there is a little piece of husk or something. Don't worry about all the cloudiness you are seeing now. It is likely tons of protein and who knows what else from husk particles. You yourself admitted you didn't get a good filtering effect in your experiment. What is your planned Mash Tun design for when you do this for real? So long as your design doesn't involve something stupid, you'll be fine.

Anyways, use iodine. Sometimes a mash is done in less than 60 minutes... In that case the extra time is just wasted time. It's so cheap, easy, and undeniably accurate there is no reason not to... unless you just don't care like phenry

 

[Bigscience]

An iodine test will not really tell you when your mash is done. I'm Iodine negative after about 15 minutes (I recirculate) but my gravity continues to rise until 30 minutes. Iodine reacts with longer chain starches (Amylose or Amylopectin, I can't remember which).

The best way to tell it to monitor with a refractometer and mash until your gravity stops increasing.

 

[KuntyBrew]

The suggestion about an iodine test is a good one - just be careful the iodine doesn't come in contact with anything you're going to eat or drink.

:cross:why i ingest iodine all the time, but thats because of the radiation I'm exposed to from my nuke i keep in the basement next to my fermenters
it wont hurt with a drop accidentally makes contact

 

[MachineShopBrewing]

why i ingest iodine all the time, but thats because of the radiation I'm exposed to from my nuke i keep in the basement next to my fermenters
it wont hurt with a drop accidentally makes contact

Your thyroid must be going crazy with that nuke in the basement and all you are taking is iodine.

Potassium iodide on the other hand might help some...

 

[Jklinden]

One drop of iodine in a quart will purify any water of bacteria, use it all the time when camping and drinking stream water

 

[Germelli1]

An iodine test will not really tell you when your mash is done. I'm Iodine negative after about 15 minutes (I recirculate) but my gravity continues to rise until 30 minutes. Iodine reacts with longer chain starches (Amylose or Amylopectin, I can't remember which).

The best way to tell it to monitor with a refractometer and mash until your gravity stops increasing.

Wouldn't the starches already contribute to gravity even before conversion? Not picking a fight, I am just curious!

I feel like any contribution to increase of gravity would be from the starches/sugars be seperated from the grain chunks and disolved in the water regardless of conversion.

 

[Bigscience]

Wouldn't the starches already contribute to gravity even before conversion? Not picking a fight, I am just curious!

I feel like any contribution to increase of gravity would be from the starches/sugars be seperated from the grain chunks and disolved in the water regardless of conversion.

If you mashed flour this would be true.

 

[shafferpilot]

hahaha. busted. iodine test works. use it!

 

[Germelli1]

If you mashed flour this would be true.

That makes no sense to me. How can sugars just be spontaneously appearing to raise density of wort? The change in gravity reading have to be attributable to something being increasingly disolved in the wort and I don't see how you can discern whether it is starches or sugars just from a refractometer.

 

[Bigscience]

That makes no sense to me. How can sugars just be spontaneously appearing to raise density of wort? The change in gravity reading have to be attributable to something being increasingly disolved in the wort and I don't see how you can discern whether it is starches or sugars just from a refractometer.

So the instant you dough in your mash will be at the gravity due to starches? Think about it this way, if you put a piece of rock candy in water, the gravity will keep rising until the sugar is fully dissolved. Also, the iodine test only is positive for over a certain amount of Amylose units, I want to say it's something like 14, but I'm on my phone away from my notes/books so I cant say for certain.

I'm brewing next week, I'll do the Iodine test and take readings to show you what I mean.

 

[shafferpilot]

Oh for gosh sakes.... THE IODINE TEST WORKS. Stop arguing against it. I understand you want to wow us with your science prowess, but it just isn't accurate. Here's the situation boiled down:

Gravity increases as stuff disolves (both starch and/or sugar)
Iodine reacts with starch - if there is no reaction (takes about an hour to get there) the conversion is done.

That's it, that's all, let's move on to actually making beer already!

 

[Clementine]

Thank for the banter guys and the practical and theoretical based advice,

As I said before I like to know the theory but when the rubber hits the road it is nice to know what works for others. I'm off to do my theory research will be playing with tests later.

Clem

 

[BWN]

I heard on a basic brewing radio podcast(I have no idea which one) that you sometimes can have conversion in as little as 5 minutes and the reason most homebrewers do 60 minutes is because that is what they have always done.

 

[Bigscience]

Oh for gosh sakes.... THE IODINE TEST WORKS. Stop arguing against it. I understand you want to wow us with your science prowess, but it just isn't accurate. Here's the situation boiled down:

Gravity increases as stuff disolves (both starch and/or sugar)
Iodine reacts with starch - if there is no reaction (takes about an hour to get there) the conversion is done.

That's it, that's all, let's move on to actually making beer already!

Sorry to try to bring some science to the table. The OP asked when to stop mashing and the answer was when the iodine test is negative. I disagreed with this in that the Iodine test can only show you that you need to keep mashing and not that you can stop. Think of it as the bubbling airlock. Bubbles mean there is fermentation but lack of bubbles does not mean lack of fermentation. Stop your mash as soon as you get an Iodine negative and you can end up with poor efficiency, high FGs and possible chill haze.

Don't take my word for it, here is a thread that talks about it and the BBR experiment that addressed this topic:

http://www.thebrewingnetwork.com/forum/viewtopic.php?f=&t=24368#_thread

Finally, I'm not saying that he Iodine test doesn't work, I'm saying that it is useless for determining when a mash should be stopped.

 

[Bigscience]

And this from Kai:

http://www.thebrewingnetwork.com/forum/viewtopic.php?f=2&t=15367&start=0#_thread

Matt, you ask 2 popular starch conversion related questions. Let me take a stab at them.

Let's say you mash at 154 for 30 min, and you have "complete conversion". Will a beer made with this wort be significantly different than if the exact same mash had been allowed to continue for a full 60 min?

Yes, I think mashing for an additional 30 min makes a difference. There should still be sufficient b-amylase activity to increase the fermentability and a-amylase can create fermentable sugars as well although it has a lower affinity to short dextrin chains and as a result is not very efficient at this.

But it also matters what you call “complete conversion”. If it means a negative iodine test there can still be starches in the grist that have not been gelatinized and converted yet. A longer rest may be able to get to them which will increase your efficiency.

If you are planning to move to a 30 min rest for some of your beers you may be able to do that. To counteract the lower attenuation that a shorter rest will give you need to mash at a lower temperature. But that means that conversion in general will slow down and there will be a lower time limit at which you are still able to produce iodine negative wort and reach the targeted fermentability. In general, the lower the desired fermentability the shorter of a mash time you can get away with.

Another test you can make is testing the level of conversion that has already happened in the mash. After 30 min of mashing, take a representative wort sample and test its gravity (works best with a refractometer). Then continue mashing and take samples at 45 min and 60 min. As long as the gravity is increasing you are converting more starch in the mash and your efficiency is increasing. The gravity limit that you can hit depends on the extract potential of the malt and the water/grist ratio. It can be used to asses mash performance and I termed it conversion efficiency.

What if during that second half-hour the temperature fell 5 degrees, would mash enzymes continue to make shorter chain dextrins from your "fully converted" but longer chain dextrins?

Dropping the temperature will do two things: slow the rate of enzyme denaturation (especially b-amylase and limit dextrinase) and slow the rate of enzymatic reactions. Because of the slower decrease of b-amylase and limit dextrinase the wort will become more fermentable if the temperature drops. To what extend? I don’t know. It might be significant or not. If it is something that always happens with your system you can compensate for this by starting the mash at a slightly higher temperature.

I hope this helped.
Kai

 

[jetmac]

Let's say we do get conversion in 10-15min; Do you think a longer rest adds anything to the flavor or body of the beer?

 

[samc]

Initially I thought that I must mash 60 minutes because that's what all the recipes say. Then I recall hearing a Vinnie C/Russian River interview where he talks about a 20-30 minute mash and the light bulb went off. Modern malts convert pretty rapidly, although I don't do 20-30 minutes I have no problem with doing 45 minutes and then a mash out to get it done. My tests doing 90 minute mashes proved to me that I was wasting 45 minutes by doing a 90 minute mash. Iodine test is great early on in brewing, but at some point you realize it isn't of much value to you when you realize what is going on.

 

[Yooper]

Let's say we do get conversion in 10-15min; Do you think a longer rest adds anything to the flavor or body of the beer?

I've had conversion in as little as 20 minutes while mashing at 158! But I usually mash 45 minutes or so anyway.

From John Palmer: Starch conversion may be complete in only 30 minutes, so that during the remainder of a 60 minute mash, the brewer is working the mash conditions to produce the desired profile of wort sugars. Depending on the mash pH, water ratio and temperature, the time required to complete the mash can vary from under 30 minutes to over 90. At a higher temperature, a stiffer mash and a higher pH, the alpha amylase is favored and starch conversion will be complete in 30 minutes or less. Longer times at these conditions will allow the beta amylase time to breakdown more of the longer sugars into shorter ones, resulting in a more fermentable wort, but these alpha-favoring conditions are deactivating the beta; such a mash is self-limiting.

 

[jetmac]

I've had conversion in as little as 20 minutes while mashing at 158! But I usually mash 45 minutes or so anyway.

From John Palmer: Starch conversion may be complete in only 30 minutes, so that during the remainder of a 60 minute mash, the brewer is working the mash conditions to produce the desired profile of wort sugars. Depending on the mash pH, water ratio and temperature, the time required to complete the mash can vary from under 30 minutes to over 90. At a higher temperature, a stiffer mash and a higher pH, the alpha amylase is favored and starch conversion will be complete in 30 minutes or less. Longer times at these conditions will allow the beta amylase time to breakdown more of the longer sugars into shorter ones, resulting in a more fermentable wort, but these alpha-favoring conditions are deactivating the beta; such a mash is self-limiting.

Hmmm...That's interesting. So if I understand what JP is saying, even though I would get conversion in 30 min, a longer rest(longer than 30 min) could help my yeasties do their job. So a 60 min rest won't hurt but could help.