I have a "crushing" efficiency question about crush vs time

[odie]

I currently mash about 10 hours...this is ONLY because I mash in before work and let it sit all day (temp controlled) and brew when I get home. I do this because it cuts down on my actual time spent.

My question is...since I am mashing for an extended time...is there any difference or advantage in conversion efficiency between grain that is crushed very fine for BIAB over a standard or "coarse" crush for a traditional mashing?

I know a finer crush will achieve full conversion in a shorter period of time.

But since I am letting the mash go for hours anyway...would a much coarser crush still reach the same full conversion efficiency, but just taking longer to happen? I figure when I pull the BIAB bag, a coarser crush will drain much faster and more completely with less squeezing.

 

[RM-MN]

I think the answer is that a coarser crush will get a slightly lower conversion efficiency. The reason is that it takes time to gelatinize all the starch and even with that it is possible that not all the starch will be fully gelatinized. My reasoning for this is based on caramel malts where they are "stewed" for some time before being kilned which gives them a bunch of sugars but if you add them to a mash after crushing you will get a little more starch converted to sugar, starch that just hadn't gelatinized. The variable is in the quality of the crush. Caramel malts are not crushed at all while you mention a "coarser crush" which can mean anything from a pretty decent crush to the grains being mostly cracked open. With a reasonably good crush I don't think you have the laboratory equipment to be able to measure the difference.

Now add in lauter efficiency and see if that makes a difference.

 

[odie]

Question is not really so much about lauter efficiency. I want to know more about conversion prior to lauter.

By "coarser crush" I mean not the tight BIAB crush that is typically used. But really just the "standard" crush that a home brew store would do or what you would do yourself if you were using a regular 3V system.

Time is not a factor in my situation. Most conversion happens probably in the first 20-30 minutes. I've got 8-10 hours.

If I can achieve the same conversion efficiency results with either a fine or regular crush...but then have a better lauter efficiency with a more normal crush, then my mash efficiency could improve.

 

[RM-MN]

Question is not really so much about lauter efficiency. I want to know more about conversion prior to lauter.

By "coarser crush" I mean not the tight BIAB crush that is typically used. But really just the "standard" crush that a home brew store would do or what you would do yourself if you were using a regular 3V system.

With that long mash and the normal crush I doubt you would see the difference between that and a very fine crush.

 

[odie]

With that long mash and the normal crush I doubt you would see the difference between that and a very fine crush.

That's what I am assuming. I just don't know if a "normal" crush, that some starches just remain "locked away" where the water can't penetrate. Or does time overcome that?

With the fine BIAB crush, there is basically no starch that the mash water can't reach fast and convert to sugars.

 

[balrog]

I honestly cannot believe 10 hours on any crush wouldn't gelatinize and convert anything. But folks like @RM-MN are far more knowledgeable than I.

 

[TheMadKing]

I'll also let the more knowledgable folks chime in, but based on my experience if you're mashing for 10 hours I think you could have barely cracked grain and it would fully convert. Osmotic pressure is at work in a mash and given that amount of time, all you need is a crack for water to get into the kernal and it will convert the starch inside the kernal, then the sugar will equilibrate between the kernal and the water

 

[RM-MN]

I'll also let the more knowledgable folks chime in, but based on my experience if you're mashing for 10 hours I think you could have barely cracked grain and it would fully convert. Osmotic pressure is at work in a mash and given that amount of time, all you need is a crack for water to get into the kernal and it will convert the starch inside the kernal, then the sugar will equilibrate between the kernal and the water

Based on how caramel/Crystal malt is made I think you are right although it is reported that adding caramel malt to the mash will get you a little more sugar than would be gotten just from what the info claims so there might be a little unconverted starch left.

 

[TheMadKing]

Based on how caramel/Crystal malt is made I think you are right although it is reported that adding caramel malt to the mash will get you a little more sugar than would be gotten just from what the info claims so there might be a little unconverted starch left.

Caramel/Crystal malts contain a mixture of different length sugar chains including glocose, maltose, maltotrios, dextrine and some other more exotic compounds. So crystal malt will always boost the original gravity of a wort, and it will almost always boost the FG of a beer meaning that some of the crystal malt sugars are unfermentable (dextrose and higher). I don't know the exact process for making crystal malt other than that its soaked and then roasted, but since it's not cracked first it seems unlikely that the soaking results in 100% conversion inside the kernal.


You're also forgetting about the part where crystal malt is roasted - the starch may indeed be fully converted prior to roasting (I'm not sure) but then maillard reactions and caramelization would both cause complex hydrocarbon compounds that are unfermentable to be formed.