Cold Steeping and Mashing

[MAiton]

I have been doing some reading on Cold Steeping and I have ran into some road blocks that have me a bit puzzled.

This is what I know,

From the book "Brewing Classic Styles" it states that malts are broken into four categories
1. Base Malts
2. Kiln Malts
3. Roasted Malts
4. Kiln-and-Roasted Malts

Base malts having the most amount of "diastatic power" and kiln-roasted malts having the least amount or next-to-none, according to some sources.

Now, steeping in general is very similar to mashing, as long as the temperature falls within the same range as that of mashing. Hence why steeping is normally only discussed when using using a recipe that includes both extracts and specialty grains. Cold steeping on the other hand, eliminates sharp off flavors of roasted grains by utilizing room temperature water that extracts just the desired flavors and colors. I know that the cold steeped grain has been recommended to be added during the last 10 minutes of the boil.

Now to my questions...

First off, if some dark malts have limited or no fermentable sugars left, why do brewing calculators typically show so much fermentable sugar in these malts? And if there is a reasonable amount of fermentable sugar available in dark malts, shouldn't the temperature that any specialty grain is steeped at impact the gravity of the beer?

Here is the brewing calculator that I play with:

https://www.brewersfriend.com/homebrew/recipe/calculator

Secondly, I found the following experiment that someone attempted which compares cold steeping against full mashing:

http://brulosophy.com/2017/12/04/roasted-grains-pt-4-cold-steeping-vs-full-mash-exbeeriment-results/

How can the fully mashed brew end up exactly the same as the cold steeped and partially mashed brew? Is this not saying that there are in fact no fermentable sugars being pulled from the dark malts?

I feel as if the brewing calculator is telling me that most of these dark malts have a significant amount of fermentable sugars whereas the experimental results prove that it doesn't matter what you do with the dark malts because it will yield the same numbers in the end.

I'm trying to gain a full understanding of what is happening so that I can accurately formulate my own recipes.

Mike

 

[thehaze]

Roasted malts can be added in the last minutes of the mash, and not the boil.

Some roasted malts can have some sugars, but it depends on the type of malt and the roasting level/process. Roasted malts add unfermentable sugars. This means, these sugars will not be transformed into alcohol, unless you break them by adding enzymes and maybe adding diastaticus/brett yeast to the wort? A calculator does not take these details into account ( I think ), thus leaving the user, the option of adjusting the yeast attenuation % to somehow better aproximate a real-life result.

Let's take US-05/Chico. It's attenuation is around 80% with all 2-row. The attenuation will drop once 10-20% of the same recipe is replaced with Crystal and Roasted malts. The OG will not be the same, close, but not the same. In theory, the calculator will leave the attenuation at 80%, thus resulting in almost the same % of alcohol, but the reality is, that those specialty malts, add unfermentable sugars, which will not be broken down by the yeast. The attenuation will probably drop to around 75%, more or less. But again, this is one of those things, the brewer must take into account when designing recipes. All these variables will have an effect on the final result.

 

[MAiton]

Some roasted malts can have some sugars, but it depends on the type of malt and the roasting level/process. Roasted malts add unfermentable sugars. This means, these sugars will not be transformed into alcohol, unless you break them by adding enzymes and maybe adding diastaticus/brett yeast to the wort? A calculator does not take these details into account ( I think ), thus leaving the user, the option of adjusting the yeast atten

And the reason we mash is so that enzymes can convert starch into fermentable sugars. But what about these unfermentable sugars? Are they still released in cold steeping similar to that of mashing?

 

[IslandLizard]

I'm with @thehaze on sugars and dextrin contributions from specialty and other kilned/toasted/roasted malts.
But I am wondering too how the extraction potential of 1.028-1.035 (per pound per gallon) breaks down with those malts. Most of them benefit from mashing (together with a diastatic, base malt) to convert certain starches into sugars and dextrins, which you won't get if just steeped.

Crystal and Caramel malts are different, they are mostly sugars, since these are malts that were mashed inside the kernels, then kilned. Due to the process they contain lots of unfermentable sugars, which yield their signature residual sweetness and associated flavors.

AFAIK, Crystal and Caramel malts as well as very dark roasted malts and grains are the only ones that can be steeped or mashed with the same (or very similar) results, yielding the same amount of sugars and color in either process.

I prefer to steep (very) dark roasted malts on the side during the boil, and add the dark or black potion after the boil, when the wort has been chilled to around 170F. They remain at that temp for 10 minutes to pasteurize, but never get boiled. I think their flavor is fresher and better that way, none of that boiled coffee character I often taste after being boiled for an hour.

 

[IslandLizard]

And the reason we mash is so that enzymes can convert starch into fermentable sugars.

Yes.

But what about these unfermentable sugars? Are they still released in cold steeping similar to that of mashing?

As long as they are water soluble, the yield should be the same, whether mashed, hot steeped, or cold steeped. Now most molecules dissolve faster, better at warmer temps than colder ones (exceptions noted, e.g. Gypsum), so that could play a role in how efficient the chosen process is. Plus the grain traps some of the liquor, so a sparge or 2 will increase extraction efficiency, in either process.

If there is nothing that can break those (unfermentable) sugars, dextrins, and flavor products up into other components or fermentable molecules, they'll remain that way until we drink it.

Maybe the more important question is:
Can mashing kilned/toasted/roasted grains convert and extract flavor components, that steeping (hot or cold) can't?
Possibly someone in the Brew Science forum can answer that or point to research.