So I am kind of just starting off doing partial mashes (done a few, came out good). A resource that is VERY helpful for noobs is DeathBrewer's Easy Partial Mash Brewing (with pics) thread. Easy to follow, explained in terms that can be easily understood, etc.
When using this guide for the first time, a new partial brewer will follow each step to a T. In step 1, DeathBrewer mentions that he heats his strike water up to 164°F as he will typically experience a 12°F loss of temp from the grains. He then proceeds to not guarantee that 164°F will bring your mash to the right temp and that we should use Green Bay Rackers Mash Calculator.
No problem here. When a new partial brewer clicks on said link to figure out what his strike water temp should be, he is greeted with a strike temp calculator that asks for your mash thickness. One who is new to partial brewing will have an instant question something along the lines of, "now what in the hell is mash thickness????"
In lurking, I have come to realize that thickness is simply a quart to pound ratio that when input in the calculator will effectively guide you to the correct temp for your strike water to compensate for heat loss from added grain. Great. I get that.
However, how does one determine what thickness to use in the first place? I see that 1.25 is pre-set in the calculator and DeathBrewer uses roughly 2 gallons of water for 5-6 pounds of grain (giving him a thickness of 1.6 for 5 gallons and 1.33 for 6).
Is this a set estimated value (oxymoron anyone?); do people simply stick around 1.25? How does mash thickness effect efficiency over the course of the brew? What are the benefits of using a thicker or thinner mash? Can you think of any other questions that a noob might have?
CONCLUSION (as taken from responses to this thread):
New brewers are worrying to much about this! Follow the directions by DeathBrewer and don't worry too much about your mash thickness if you are just starting out with partial mashing.
Mash thickness is simply a quart to lb ratio of water to grain. A good general guideline is to have a thickness of about 1.25 quarts of water per pound of grain (1.25 for short). If you plan on Brewing In A Bag (BIAB), you can go upwards of 3, but anywhere within the 1-2 range is generally good.
Think of it like this: Imagine you are a youngster and want to play Marco-Polo with some friends, but in this game, you have to try to find as many people as you can. If you play in a too big of a pool, you would spend too much time trying to find everyone and might not even get everyone. Conversely, if you were to play in a kiddie pool, you wouldn't be able to get around to get everyone. Essentially, you are the enzyme trying to find your starch friends to tag them and turn them into sugar. You want to keep the enzymes concentrated and on the starches; not swimming around in some huge pool of water looking for them. You also don't want everything to be so crowded in there that nothing can move.
If you mash to thick (lower ratio), your grains will not get wet enough and there may be too many undissolved starches in your wort. Too thin (higher ratio) and you may have difficulty getting the mash pH low enough, and this could lead to conversion problems. Also, if your mash is too thin, you are going to have less water to sparge with later on.
Different grains or styles may require different thicknesses, but in short, mash thickness is really more a personal preference than a "hard calculation that could ruin your whole brew." Keep in mind your tun size when choosing thickness but really, don't sweat it!
Relax, don't worry, have a homebrew, you newbs!
When using this guide for the first time, a new partial brewer will follow each step to a T. In step 1, DeathBrewer mentions that he heats his strike water up to 164°F as he will typically experience a 12°F loss of temp from the grains. He then proceeds to not guarantee that 164°F will bring your mash to the right temp and that we should use Green Bay Rackers Mash Calculator.
No problem here. When a new partial brewer clicks on said link to figure out what his strike water temp should be, he is greeted with a strike temp calculator that asks for your mash thickness. One who is new to partial brewing will have an instant question something along the lines of, "now what in the hell is mash thickness????"
In lurking, I have come to realize that thickness is simply a quart to pound ratio that when input in the calculator will effectively guide you to the correct temp for your strike water to compensate for heat loss from added grain. Great. I get that.
However, how does one determine what thickness to use in the first place? I see that 1.25 is pre-set in the calculator and DeathBrewer uses roughly 2 gallons of water for 5-6 pounds of grain (giving him a thickness of 1.6 for 5 gallons and 1.33 for 6).
Is this a set estimated value (oxymoron anyone?); do people simply stick around 1.25? How does mash thickness effect efficiency over the course of the brew? What are the benefits of using a thicker or thinner mash? Can you think of any other questions that a noob might have?
CONCLUSION (as taken from responses to this thread):
New brewers are worrying to much about this! Follow the directions by DeathBrewer and don't worry too much about your mash thickness if you are just starting out with partial mashing.
Mash thickness is simply a quart to lb ratio of water to grain. A good general guideline is to have a thickness of about 1.25 quarts of water per pound of grain (1.25 for short). If you plan on Brewing In A Bag (BIAB), you can go upwards of 3, but anywhere within the 1-2 range is generally good.
Think of it like this: Imagine you are a youngster and want to play Marco-Polo with some friends, but in this game, you have to try to find as many people as you can. If you play in a too big of a pool, you would spend too much time trying to find everyone and might not even get everyone. Conversely, if you were to play in a kiddie pool, you wouldn't be able to get around to get everyone. Essentially, you are the enzyme trying to find your starch friends to tag them and turn them into sugar. You want to keep the enzymes concentrated and on the starches; not swimming around in some huge pool of water looking for them. You also don't want everything to be so crowded in there that nothing can move.
If you mash to thick (lower ratio), your grains will not get wet enough and there may be too many undissolved starches in your wort. Too thin (higher ratio) and you may have difficulty getting the mash pH low enough, and this could lead to conversion problems. Also, if your mash is too thin, you are going to have less water to sparge with later on.
Different grains or styles may require different thicknesses, but in short, mash thickness is really more a personal preference than a "hard calculation that could ruin your whole brew." Keep in mind your tun size when choosing thickness but really, don't sweat it!
Relax, don't worry, have a homebrew, you newbs!