How to tell when conversion is complete

[foxy]

I stopped doing Iodine tests years ago as I have never had a problem it had a 80% BHE and over 2 points above predicted SG

I hadn't done them for years then I read on Voyagers website how quickly the grist converts and it piqued my interest, so I read up on the speed which conversion takes place for different grains. American six-row is the fastest with pilsner second but it can change with different maltsters.

 

[Sadfield]

I stopped doing Iodine tests years ago as I have never had a problem

That's the second Iodine test, passed. The point when your confident your process is good.

I only reach for it when I'm doing something way out of the ordinary.

 

[Sorcerers Apprentice]

Just checking its dextrose that you're using for carbonation, and not maltodextrin , as maltodextrin is a complex sugar and not easily broken down by yeast

 

[Vinylwasp]

I agree with Sadfield and Caramel Ox. Putting the numbers into a brewhouse efficiency calculator they have based it on an 80% efficiency (which is difficult to achieve in home brewing) and you have achieved 65% (which is on the low side but not unheard of. I generally get 70% efficiency but occasionally it will drop to about 67%). You have about 4.6kg of grain in the kit but for a 1048 at about 33 litres I would normally have nearer 5kg grain. I am not sure about the carbonation issue. 160g dextrose seems quite a lot so should have given a high carbonation.

The 80% value used in the recipe is Mash Efficiency, i.e., the potential sugar converted from the malts in the mash before system losses are taken into account (dead space, trub, transfer losses, etc). Once those system losses are deducted (1-3l or wort perhaps depending on system), then you've got your overall Brewhouse Efficiency.

My Mash Efficiency improved a lot when I started ensuring all my mashs:

• used 3l water:1kg fermentables (thinner)
• fine crush with 300g rice hulls
• stirred really well 2-3 times in first 20 minutes
• drain my MT completely before sparging
• sparge slowly (30+ minutes)

Looking at the FG I'd hazard a guess that the attenuation gap (1.012 vs target 1.008) wasn't necessarily down to the yeast performing poorly, but could have been caused by higher activity of Alpha Amylase in the mash producing slightly more dextrines due to the temp being slightly above 66. If you're aiming for that dry (under FG 1.010), I'd drop down to 65 or even 64.5c mash temp. This is one area where I think there are some questions about the accuracy of temp measurement in AIO systems. For a start I'd guess that to keep the price down they use analog temp sensors which have +/- 1 deg accuracy from factory. Then you have the location and RIMS design to consider. I don't have an AIO so can't really comment but I've seen plenty of threads on this topic.

 

[peebee]

As "dextrose" (glucose) and "maltodextrin" (a mainly unfermentable product of mashing) have been mentioned ... and you can buy maltodextrin powder but that may be totally unfermentable, or won't contain the "malto-triose" dextrin that some yeasts will ferment ... And! Iodine can't distinguish between fermentable sugars and unfermentable dextrin (well it can ... if your imagination is good or your test solution is virtually colourless (i.e. not beer!) ... Then! ... Pah!

Iodine can be considered useless at confirming whether conversion is "complete". It might indicate when there is no starch left, but that's not the same as "complete". And I'd argue that it's not much use at that either (indicating "no starch left") so I haven't used the stuff since the 1970s. Apparently, your mash test sample must be absent of things like grain which might cause false positives ( ). But it's one of those "rituals" that "have to be performed" ... (like weighing your hops only on a Friday).

 

[Sadfield]

The 80% value used in the recipe is Mash Efficiency, i.e., the potential sugar converted from the malts in the mash before system losses are taken into account (dead space, trub, transfer losses, etc). Once those system losses are deducted (1-3l or wort perhaps depending on system), then you've got your overall Brewhouse Efficiency.

My Mash Efficiency improved a lot when I started ensuring all my mashs:

• used 3l water:1kg fermentables (thinner)
• fine crush with 300g rice hulls
• stirred really well 2-3 times in first 20 minutes
• drain my MT completely before sparging
• sparge slowly (30+ minutes)

Looking at the FG I'd hazard a guess that the attenuation gap (1.012 vs target 1.008) wasn't necessarily down to the yeast performing poorly, but could have been caused by higher activity of Alpha Amylase in the mash producing slightly more dextrines due to the temp being slightly above 66. If you're aiming for that dry (under FG 1.010), I'd drop down to 65 or even 64.5c mash temp. This is one area where I think there are some questions about the accuracy of temp measurement in AIO systems. For a start I'd guess that to keep the price down they use analog temp sensors which have +/- 1 deg accuracy from factory. Then you have the location and RIMS design to consider. I don't have an AIO so can't really comment but I've seen plenty of threads on this topic.
View attachment 96240

But Lallemand's own attenuation figures for a wort prepared in that standard range is 65 - 72 %. The recipe is based on 81% attenuation.

 

[crescent city Mike]

The major purpose of mashing is to degrade proteins, gums, and starches in the grain to produce a wort which will suit our purposes as brewers. Different beer styles require a wort of specific properties. Some beers are supposed to be thick, malty, and sustaining while others should be thinner, crisp, and refreshing. The method of mashing you employ will determine the kind of beer you produce.

Crushed malt can be added to ambient temperature water and it will convert if given enough time. Of course, the chance of a bacterial or other organic infection increases over time. If a perfect environment is established including temperature, mash thickness, and pH, malted barley will convert in as little as 12 minutes. Most of us don’t have lab quality brewing conditions and equipment so we need to do things somewhere between the two extremes.

The vast majority of brewers I know seem to think that 60 minutes will do the trick. It may or may not. Old brewing records from commercial brewers show they mashed for two hours; that seems to have been standard.

Mashing isn't just about converting starch into sugar. An iodine test may indicate that conversion is complete but it usually isn’t. There are lots of different sugars in the mash and some need to degrade further to yield a balanced wort. An extra 30 to 60 minutes of mashing won’t sabotage your brew day but will surprise you in producing a better wort and subsequently, a better beer.

 

[Vinylwasp]

But Lallemand's own attenuation figures for a wort prepared in that standard range is 65 - 72 %. The recipe is based on 81% attenuation.

Yep, you're dead right and note what they say about adjusting mash temp accordingly.

LalBrew Windsor™ does not utilize the sugar maltotriose (a molecule composed of
3 glucose units). Maltotriose comprises an average of 10-15% of total sugar in all-malt
worts. The result will be fuller body and residual sweetness in the beer. Be advised to
adjust mash temperatures according to desired result.

 

[Vinylwasp]

But Lallemand's own attenuation figures for a wort prepared in that standard range is 65 - 72 %. The recipe is based on 81% attenuation.

Yep, you're dead right and note what they say about adjusting mash temp accordingly.

LalBrew Windsor™ does not utilize the sugar maltotriose (a molecule composed of
3 glucose units). Maltotriose comprises an average of 10-15% of total sugar in all-malt
worts. The result will be fuller body and residual sweetness in the beer. Be advised to
adjust mash temperatures according to desired result.

 

[Sadfield]

It'd take some extreme mashing conditions to get +80% attenuation from Windsor.

 

[Vinylwasp]

It'd take some extreme mashing conditions to get +80% attenuation from Windsor.

Yep, methinks the team from GEB dropped a replacement yeast into that recipe without checking the attenuation.

 

[Alan_Reginato]

It's a low attenuation yeast plus a high mash temperature. The FG is going to be higher and the ABV lower than the recipe's prediction.

 

[foxy]

Iodine can be considered useless at confirming whether conversion is "complete". It might indicate when there is no starch left, but that's not the same as "complete". And I'd argue that it's not much use at that either (indicating "no starch left") so I haven't used the stuff since the 1970s. Apparently, your mash test sample must be absent of things like grain which might cause false positives ( ). But it's one of those "rituals" that "have to be performed" ... (like weighing your hops only on a Friday).

Not really confirming whether conversion is complete but as an indication if there is any starch in the wort. Pro Brewers still use this method as it gives good indication in a couple of minutes whether to continue with the mash or not.
https://discussions.probrewer.com/f...es-sponsored-by-cpe-systems/46433-1-hour-mash

 

[Sadfield]

Conversion is just brewers short hand for the point where there is no more starch, the creation of fermentables, isn't it? The point where an iodine test is passed. Sugar type being irrelevant as preboil gravity readings via saccharometer (hydrometer) would be the same.

Technically, the ongoing shortening of sugar chains is saccharification, the third phase of starch degradation, after gelatinisation and liquifaction.

So conversion would be complete, saccharification completion is of the brewers determination based in desired attenuation. Ended by the denaturing of enzymes.

 

[foxy]

Conversion is just short hand for the point where there is no more starch, isn't it? The point where an iodine test is passed. Sugar type being irrelevant as preboil gravity readings via saccharometer (hydrometer) would be the same.

Technically, the ongoing shortening of sugar chains is saccharification, the third phase of starch degradation, after gelatinisation and liquifaction.

So conversion would be complete, saccharification completion is of the brewers determination based in desired attenuation.

Sugar type is irrelevant as you say in a hydrometer too. Hence so many threads on a stuck mash, that it is considered yeast to be the culprit. A test in the grain will be a greater determination of the starch present. Just one reason I prefer a more fluid mash. Braukaiser covers it nicely in his blog.

 

[peebee]

Not really confirming whether conversion is complete but as an indication if there is any starch in the wort.

That's what I said, but your phrase makes it clearer.

Pro Brewers still use this method as it gives good indication ...

But that is not what I said (), but rather than argue with it I'll repeat something I did say:

... it's one of those "rituals" that "have to be performed" ...

(Many "Pro Brewers" these days are homebrewers but with a bigger play box to play in).

 

[peebee]

Here's an extreme example:

Stuck?

Not at all. I intended it to be that way (FG1.036 ... it's an historical English "Ale" known as "Stitch" of 17-18th C. times). It was a bit of fancy manipulation of the sugars created by the mash, and most of the "sugar" was unfermentable! Anyone making their "NEIPA", using iodine, would get the "all clear" checking the mash that made the above; but they would be dismayed at how the fermentation progressed. [EDIT: Blasted century numbers being +1 on the year (hundreds) numbers ... gets me all the time! 16-17th C. changed to 17-18th! (i.e. 1600-1799).]

Obvious conclusion: Iodine is a perfectly useless tool for confirming the "completion" of a mash.

 

[Sadfield]

It's a perfectly useful tool to indicate when the mash can be completed if and when desired.

Valid enough a test for Moston Coors to bother with, from Inside The Factory, Series 4 - Episode 7, "Beer"

 

[Rodcx500z]

Maybe thats why their beer is crap

 

[peebee]

Maybe thats why their beer is ****

"Moston-Coors"! - They obviously pick the cream of the workforce there. !