Why isn't an Iodine test the "defacto" standard for mash time?

[GilaMinumBeer]

As opposed to the standard 60 minutes?

What else is going on that requires the minute term aside from flat out conversion?

 

[IrregularPulse]

The lack of ph test strips for me is what has me doing 60 minutes to be safe.

 

[boo boo]

Starch is still being broken down after full conversion has taken place,
which could make your brew drier.

 

[GilaMinumBeer]

The lack of ph test strips for me is what has me doing 60 minutes to be safe.

How does pH indicate complete conversion? Don;t think I have ever heard or read that suggested. I know pH facilitates the enzyme activity in optimal ranges.

 

[farmbrewernw]

In theory you should be able to just get to conversion, I have done 40 min mashes after determining that conversion has occurred using the iodine test, conversion could take longer than 60, that is why you should always check

 

[niquejim]

If I'm not mistaken most of the conversion is done in 60 minutes or less(As few as 20 minutes can give conversion) but that doesn't mean that there isn't more work for the enzymes to do breaking down long chain dextrins into shorter, more fermentable ones.

 

[GilaMinumBeer]

Starch is still being broken down after full conversion has taken place,
which could make your brew drier.

Debranching to limit dextrins, etc... further cleaving into simple sugars.

But if the iodine indicates there is no starch present is the mash really done?

 

[niquejim]

But if the iodine indicates there is no starch present is the mash really done?

Maybe not, depending on what you're brewing

 

[GilaMinumBeer]

If I'm not mistaken most of the conversion is done in 60 minutes or less(As few as 20 minutes can give conversion) but that doesn't mean that there isn't more work for the enzymes to do breaking down long chain dextrins into shorter, more fermentable ones.

Okay. Now that makes some sense to me. The starch may be broken up enough to pass Iodine but, further cleaving is taking place to effect the final degree of fermentability.

 

[niquejim]

Okay. Now that makes some sense to me. The starch may be broken up enough to pass Iodine but, further cleaving is taking place to effect the final degree of fermentability.

That's why a long low mash works so well for big (1.120+) beers. It helps to make it easier to get a lower final gravity even with the high start

 

[IrregularPulse]

How does pH indicate complete conversion? Don;t think I have ever heard or read that suggested. I know pH facilitates the enzyme activity in optimal ranges.

Yeah ignore me, I don't know what I was thinking about. Probably half asleep at work. Yeah that's it.

 

[GilaMinumBeer]

Yeah ignore me, I don't know what I was thinking about. Probably half asleep at work. Yeah that's it.

I do that too.

 

[IrregularPulse]

I meant Lack of Iodine at home. I never think about using an iodine test until I see mention of it on here. Never on brew day or before brew day to buy iodine.

 

[SpanishCastleAle]

I have Iodine and I almost never use it and I almost never mash for more than an hour and often rest at low-ish sacc rest temps. When I do decoctions I test the decoction for conversion and it's usually starch-negative in 10-15 minutes...but that's resting at about 158 F or so. I've never had to go more than 15 minutes converting a decoction to starch-negative.

I used to always test but after a bunch of tests with not one being starch-positive I just stopped doing it for the main mash.

Plus, when you mash-out at 168 F or 170 F you don't denature all the enzymes anyway...the alpha-amylase are actually in turbo-mode throughout the sparge...making sure the job is complete.

 

[GilaMinumBeer]

I meant Lack of Iodine at home. I never think about using an iodine test until I see mention of it on here. Never on brew day or before brew day to buy iodine.

That is where my big bottle of otherwise useless to me Iodophor comes in handy.

 

[Kaiser]

This is a good subject to elaborate on. Let me try to put this iodine test thing into the big picture:

The wort that is brought to a boil has various requirements that it needs to meet. For one it should not contain any starch or long dextrines. Those are or will become insoluble in the presence of alcohol and create the so called starch haze. A brewer can test for the presence of starches and dextrins with an iodine test and the wort should show no color reaction with iodine. At this point it is said to iodine neutral. Large breweries even do it with photometric means which simply measures the light absorption of a wort and iodine mixture. Another requirement is the fermentability of the wort. I.e. the ratio between fermentable sugars and total dry weight of extract in the wort.

Both iodine neutrality and fermentability require enzymes to get them where we want to have them. That’s what the mash is for although you should keep in mind that the enzymes, a-amylase in particular, are still active during the lauter and in the kettle until the wort hits about 180-190F. After that there is no more change and if there is a problem with excessive starches/large dextrins it cannot be fixed unless you add more enzymes.

Fermentability cannot be easily checked by a simple test that is fast enough for you to take immediate action. But iodine neutrality can. It tests if there are any starches/large dextrins left in the sweet wort. It cannot check for full conversion b/c it doesn’t tell you if there are still unconverted starches in the spent grain. But that is not that important as long as these starches don’t make it into the kettle w/o being broken down by the enzymes.

60 min mashing is a quasi standard for home brewing. Mostly b/c it works for most mashes and keeping this variable constant simplifies things. But there is nothing wrong with mashing shorter or longer as long as your fermentability, iodine neutrality and efficiency goals are met. I think the 60 min are based more a historic and pragmatic background than on any empirically evidence.

Why do I advocate an iodine test for every mash? B/c it is good practice. Just like checking your mirrors when you change lanes even though it is 2am and you are the only one on the highway. The test is easy and quick enough and while it doesn’t give much valuable information if it is negative (b/c you expected that) it is very valuable to know if you mash tests positive with iodine (negative is a good thing and positive a bad thing not that intuitive but the same with getting tested for a disease ). The latter can easily happen when you push the boundaries w/ respect to mash time, mash temp or diastatic power. I know for example that the iodine test is a very important tool when using large amounts of dark Munich malt (e.g. 100%) in a mash as this malt is enzymatically rather weak and iodine neutrality after 60 min is not a given.

If the mash tests positive for iodine you may give it some more time, add some lightly kilned malt (i.e. fresh enzymes), check the pH or simply note the fact and keep on brewing. Maybe it turns out fine. At least you have one more data point for troubleshooting problems. Those beers are called “Blausud” (blue batch) in German brewing.

Kai

 

[IrregularPulse]

Good info Kai, You are a great attribute to this community! Maybe I'll pick a bottle of iodine. you just put a drop on say a paper plate, then a drop of wort onto that?

 

[Edcculus]

Great info Kai! I'm utilizing your method of checking every batch. I started doing this because I switched to StarSan and have a small bottle of Iodophor sitting on the shelf. Only using a few drops to test each batch, my small bottle will likely go bad before I use it all.

I've messed around a little with taking tests throughout the saccharification rest. I haven't really used the info to see if I can cut mash times though. I've noticed that wort I draw off the top is converted fairly quickly. Probably withing 30-45 min. I do notice that if I take some grain early on, mash it up good on a white plate, it tests positive. That makes perfect sense.

This topic begs the question. Is any type of iodine ok to use? Drug store iodine and Iodophor are probably the most common and easily obtained.

 

[HairyDogBrewing]

Good info Kai, You are a great attribute to this community! Maybe I'll pick a bottle of iodine. you just put a drop on say a paper plate, then a drop of wort onto that?

Try that with just water first.
I'm not sure that paper is neutral wrt iodine.
I use a piece of white ceramic.
Others use a piece of sidewalk chalk.

 

[Kaiser]

This topic begs the question. Is any type of iodine ok to use? Drug store iodine and Iodophor are probably the most common and easily obtained.

I think so. If it is made for desinfection purposes then it should work. The iodine that kills the germs is also the iodine that stains the glucose helices.

There is some info of the reaction here: Carbohydrates - German Brewing Techniques

I took most of the info from here:

Starch - Iodine

Kai

 

[michaelm]

lol I just use my idophore..... man a bottle of that goes a LONG way...

I have some white ceramic plates I just grab one of them pull a little shot of clear wort(I heard you gotta be carefull because grain husk and particals will cause it to react) put it on the plate and use a peice of plastic to dip in the idophore and let a drop land in the wort sample watch it spread out and look for any black flash

 

[Edcculus]

lol I just use my idophore..... man a bottle of that goes a LONG way...

I have some white ceramic plates I just grab one of them pull a little shot of clear wort(I heard you gotta be carefull because grain husk and particals will cause it to react) put it on the plate and use a peice of plastic to dip in the idophore and let a drop land in the wort sample watch it spread out and look for any black flash

Thats exactly what I do too. Seems to work so far.

 

[SpanishCastleAle]

Here is a thread I came across that had an interesting post by 'Cargill Malt' (post #19 in that thread).

In that post Cargill Malt states:

That being said, 60 minutes is a very long conversion rest. The goal of the conversion rest is to suficiently break down the starch to get your desired wort carbohydrate profile, and to move along as soon as possible. There are deleterious effects of long conversion rests. An elucidation of these evils is beyond the scope of this post, but think about extracting lipids and polyphenols from malted barley husk. Long term stability and flavor (astringency) issues.

What are these 'deleterious effects'?

In any case, I'm brewing a Sticke Alt today and I'm gonna try a very short version of the temp-ramp mash mentioned at the end of that thread (posted by Larry). Dough-in to rest @ 144 for 5 min, ramp to 158 over 20 min, rest @ 158 for 5 min, test for conversion, mash-out @ 168. It's mostly a 1:1 mix of Pils:Light Munich with a little Caramunich and a tiny bit of Carafa Special II.

Should one of the (possibly overlooked?) benefits of crushing your own grain and getting a nice, fine crush be that you can shorten sacc rests?

 

[BierMuncher]

...I'm brewing a Sticke Alt today and I'm gonna try a very short version of the temp-ramp mash mentioned at the end of that thread (posted by Larry). Dough-in to rest @ 144 for 5 min, ramp to 158 over 20 min, rest @ 158 for 5 min, test for conversion, mash-out @ 168. It's mostly a 1:1 mix of Pils:Light Munich with a little Caramunich and a tiny bit of Carafa Special II....

I'm guessing a 30 minute mash tie will be plenty for conversion, but your attenuation will be substantially less.

 

[boo boo]

Plus I don't think a mash of 60 to 90 minutes will cause any problems with lipids or polyphenols with a good crush at normal mash temps.

Kai... do you mind if I copy your post and paste it to my club e-mail site?

 

[menschmaschine]

What are these 'deleterious effects'?

I'm not sure I agree with the implication made by Cargill that long conversion rests are inherently a bad thing. In the Hochkurz mash schedule, the conversion rests can go for a total of up to 2.5 hours. I think it can be a bad thing if the brewer is not conscious of this possibility doesn't compensate for it. The risk of lipids and polyphenols from the mash can be reduced by good lauter techniques (correct temperature & pH, clear wort) and good rolling boils (hot break).

 

[RonRock]

Good read.

 

[HenryHill]

In the scrambled mash that I possess for brain matter is a fuzzy memory of a thread somewhere on the tubes that mentioned Macros mashing for up to 3 hours, to provide the driest outcome possible.

Just like with low end mash temps, mash times over an hour provide a somewhat drier end result, and can be another variable in recipe to assist in the character of your recipe.

As was stated, for basic high-diastatic grain bills, 20 minutes can be enough to convert the starch, but like conditioning beer can greatly improve flavor, longer mash times can improve attenuation, when it is desired.

60 minutes is the happy medium for generic purpose, and it provides a convenient time period for accomplishing all the other peripheral tasks of a brewday, and you can get in a couple of pints of brew, easy.

 

[Edcculus]

Just had an idea. If as the Cargill literature states, long rests can extract unwanted compounds from grain husks. I wonder if there would be any advantage of doing a 30 min sacc rest followed by a sparge the same temp as your rest. If you aren't using hot water, conversion will continue during the sparge. Lets say it takes 15 min to double batch sparge. By then you are up to 45 min. Even with a gas burner, it takes at LEAST 10min to get the temp above 165-170 when the enzymes will be denatured.

Of course, the enzymes will be very diluted after the sparge, but they will still be working.

 

[SpanishCastleAle]

The alpha-amylase enzyme isn't fully denatured at regular 'mash-out' temps of 168-170...what is left of it is working in turbo-mode. It's usually working throughout the lauter/sparge and up until you get the boil kettle up high enough to fully denature. I can't find the reference right now...Sticke is boiling. I think I saw it on Kaiser's site somewhere (although I prob mis-worded it).

FWIW, I just finished that short mash and my efficiency was nominal and it was converted when I tested it. I think it was converted before I rested @ 158 for 5 min but I didn't test it then. But as pointed out...the real question will be the attenuation. I will report back when it finishes.