Maltose diffusion rate

[Delaney]

Hi there,

I am curious as to whether the presence of fructose and glucose in apple cider would reduce the diffusion rate of maltose? I'm inclined to think no...

If so, would this not imply that you could use apple cider as your mash and sparge water while maintaining normal maltose extraction efficiencies?


Second question: can the enzymes provided by base malts convert starches from apples for example? I don't see why not....I know it would cause ridiculous pectin haze, but could one not simply mash with pure base malts, sparge grain, then do a mash with crushed apples? I know it sounds crazy, but I don't see why it wouldn't work lol.

 

[JimRausch]

Hmmm. Interesting. I'm going to follow this one when the ones more knowledgeable in chemistry chime in. But here's my thoughts from biology and chemistry 1st learned 30 years ago:
Diffusion for different compounds are independant of each other. But I'm sure that diffusion is not the right term for what happens in the mashing process, and I'm not sure it is accurate for sparging either.
So, I don't think the sugars in apple juice will interfere with the enzymatic production of maltose and other sugars in your mash. And I don't think they would interfere with your rinsing of sugars out of the mash in the sparging process. But where there might be a problem is in the pH of the apple juice. I believe it's well below the 5.2-5.6 range and might interfere with the activation and action of the enzymes. But will it be adequately buffered by the mash? That's a Q I don't have the chemistry for.
Your other Q about enzymes in malt being effective on apples is also interesting. I'm sure there is no pectic enzyme in malt, so the cloudiness from pectin won't be changed. Is there starch in apples, or just sugars? I don't know that either. I'm thinking just sugars or cider would need some source of amylase prior to fermentation.
I look forward to those more knowleagable to chime in.

 

[Delaney]

Hmmm. Interesting. I'm going to follow this one when the ones more knowledgeable in chemistry chime in. But here's my thoughts from biology and chemistry 1st learned 30 years ago:
Diffusion for different compounds are independant of each other. But I'm sure that diffusion is not the right term for what happens in the mashing process, and I'm not sure it is accurate for sparging either.
So, I don't think the sugars in apple juice will interfere with the enzymatic production of maltose and other sugars in your mash. And I don't think they would interfere with your rinsing of sugars out of the mash in the sparging process. But where there might be a problem is in the pH of the apple juice. I believe it's well below the 5.2-5.6 range and might interfere with the activation and action of the enzymes. But will it be adequately buffered by the mash? That's a Q I don't have the chemistry for.
Your other Q about enzymes in malt being effective on apples is also interesting. I'm sure there is no pectic enzyme in malt, so the cloudiness from pectin won't be changed. Is there starch in apples, or just sugars? I don't know that either. I'm thinking just sugars or cider would need some source of amylase prior to fermentation.
I look forward to those more knowleagable to chime in.

Sparging relies on diffusion. That is why fly sparging works. Obviously diffusion does not encompass all aspects of mashing, but it's integral to that process. If the diffusion of maltose were somehow inhibited by fructose and what not (which I doubt) then that would have implications for reactant and product concentrations in and around the grains, which would in turn effect reaction rates (enzyme activity), which would in turn affect brewhouse efficiency.

Your point regarding pH is a good one, however..

I`ve taken two chemistry courses and I am currently studying in biochemistry. I just figured there might be more experienced chemists here who could better think through my idea.

 

[pjj2ba]

Sparging is chromatography, in particular, most similar to size exclusion chromatography as opposed to an affinity type. As water is added on top (fly sparging) it simply pushes the sugar solution out the bottom (or wherever the outlet is). If one were to measure the sugar concentration coming out it would result in a bell shaped curve. Some of the sugar gets "trapped" in the small pores of the husks and other material left over after conversion and these sugars have a much longer path to follow to get to the outlet, giving rise to the tail of the peak.

I don't think the composition of the sugars will make any difference on this process as they are all similarly sized (relative to the porosity of the chromatography bed). They all will behave the same. Any difference would be simply from having more sugars, not that they are specifically interfering with one another