Thin Mash

[GrundleCruncher]

I've been experimenting with my mlt I made from a 5gal rubbermaid. My mash is pretty thin but the temp is spot on. I have 3 lbs of grain in with about 1.5, maybe 2 gal.
I was wondering what the consequences of this thin of a mash would be, are there any benefits from a thin mash?

 

[GrundleCruncher]

It tastes like I got a poor starch conversion

 

[Funkenjaeger]

I'm no expert on the matter, but I believe that a thin mash messes things up because with a more dilute solution the enzymes aren't in contact as much with the sugars and thus can't convert them as quickly/efficiently. Your tasting note seems to support this. Did you mash any longer than usual?

 

[the_bird]

Well, a really THIN mash would be about 2qts/lb, so if you've got 1.5 gallons, that's about as thin as you would ever really see. The consequences of going thinner, I couldn't tell you. What thin mashes in general will do is promote a more-fermentable wort. The effect is not as pronounced as if you lowered the temperature, but it's there.

 

[GrundleCruncher]

After mashing for 1hr 30min and sparging, boiling and cooling the wort tasted pretty bitter. The gravity good at 1.053.
I used 1oz. 6%AA for a boil gravity of about 1.8 so I didn't think it would be too bitter from the hops.
Is this a consequence of a poor conversion and boiling a bunch of starch?

 

[The Pol]

I have done thick and thin mashes... a thinner mash in theory will take longer to convert, but 90 minutes should be plenty. I have never noticed much of a difference in my beer with a thick or thin mash, as I always mash for 90 minutes, there is always complete conversion.
I will tell you that I have ALWAYS had bitter tasting beer after the boil, from the hops, it has always been pucker my face bitter... I would not classify that as incomplete conversion.

 

[DAAB]

There's little difference but a thinner mash in theory produces a more fermentable wort. Temperature is a far more important factor though.

 

[boo boo]

A thin mash of more than 2 Qts per Lb of grain dilutes the concentration of enzymes and slows conversion. It will give a more fermentable mash because the enxymes aren't blocked as much by a lot of concentrated sugars.
Too much dilution of the mash and then time takes over. Enzymes are denatured over a long period of time.
Thickness and thinness of the mash is only one factor in mash development.

Temperture and Ph of the mash also take an important role in the mash.

 

[DAAB]

A thick mash is beneficial for starting the reactions and converting the starch to sugars but once the starch has been converted to dextrins these sugars restrict the enzyme that produce the more fermentable maltose sugars so one is played off against the other.

 

[Thalon]

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.

http://www.howtobrew.com/section3/chapter14-6.html

 

[DAAB]

and results in a faster overall starch conversion,

Conversion can take as little as 20 mins, it takes longer to achieve the correct balance of sugars.