Mash thickness

[Gunkleneil]

So how much does mash thickness matter? I had 13.5 lbs of grain in a BIAB with 8.75 gallons of water in a 60qt pot. The grains were floating around very loose in the water. Does that affect my efficiency of sugar production? Is a thicker more porridge like mash better for starch conversion? This was my first all grain and first time using this pot. So I have a bit of a curve still to go.

 

[Megary]

Here’s one data point.
I strictly do BIAB and played around with this a lot. I found I got better conversion (sometimes much better) with a greater Vol:Grain ratio, a thinner mash. But since I full-volume mash, thinner mashes mean longer boils to hit the proper volume. So I only do extra thin mashes when I absolutely need to max out on conversion, usually that means Big Beers.

Cheers.

 

[Gunkleneil]

Thanks for sharing your experience. I was aiming for a post boil gravity of 1.057 at 5 gallons after a 60 minute boil. But ended up with 1.050 with 6 gallons after a 90 minute boil to try to bring my volume down. I have since adjusted my equipment profile to use less water. So I figure I'm off on the gravity due to the extra gallon.

 

[Mark Farrall]

Yep, too much water was 90 odd percent of the reason for your issue. Mash thickness can change things, but it's generally not that important.

 

[Herm brews]

It might be worth noting that here on Brewers Friend, mash thickness is not accounted for if using BIAB process. It says so when entering info in the Equipment Profile, unless something has very recently changed.

 

[Ozarks Mountain Brewery]

sparging or lautering is the real reason, less water means more water to sparge with and more possibilities to wash sugar off the grain

 

[Ward Chillington]

Does that affect my efficiency of sugar production? Is a thicker more porridge like mash better for starch conversion? This was my first all grain and first time using this pot. So I have a bit of a curve still to go.

Conversion is more a function of time and temperature so not really. I noted you adjusted your water to grain ratios...what were they and where you moving to? I do a 1.5qt for mash and 2 for sparge.

And don't fret about not hitting the numbers....just think of it as dialing in the new method....it'll still make beer!

 

[Gunkleneil]

I figured I was close enough for some good beer with the numbers I got. Not fretting. It will have alcohol. I did BIAB and squeezed out a bit of the water. No Sparge. I think I was at like 1.5qt for mash and went down to 1qt to see what happens next time. I know it will take time to dial in my profile and my experience.

 

[BarbarianBrewer]

According to John Palmer's book How To Brew (3rd edition), mash thickness "is the least significant factor impacting mash performance". However, he does say:

"The grist/water ratio is another factor influencing the performance of the mash. A thinner mash of >2 quarts of water per pound of grain dilutes the relative concentration of the enzymes, slowing the conversion, but ultimately leads to a more fermentable mash because the enzymes are not inhibited by a high concentration of sugars. A stiff mash of <1.25 quarts of water per pound is better for protein breakdown, and results in a faster overall starch conversion, but the resultant sugars are less fermentable and will result in a sweeter, maltier beer. A thicker mash is more gentle to the enzymes because of the lower heat capacity of grain compared to water. A thick mash is better for multirest mashes because the enzymes are not denatured as quickly by a rise in temperature."​

I also remember homebrewing guru Denny Conn saying (for a traditional batch sparge) he tries to have the volume of the first and second runnings to be approximately the same. e.g.: A strike water volume of 6 gallons - 2 gallons to absorption = 4 gallon first running. So, my sparge volume would then be 4 gallons.

 

[GFHomebrew]

My average mash thickness is 6lt/kg quite thin with a sparge I average 83% brew house full volume so even thinner maybe 6.5lt / kg I average around 79-80% brew house.

I recirculate my mash but I've found this hasn't contributed a great deal to my BH efficiency but on occasions I've got 87+ BH but that's been an anomaly.

Also as I thinks been mentioned big beers my efficiency had been lower traditionally but I don't brew many 5+% beer.