What is a mash rest?

[seanppp]

I've looked all over the internet and I cannot understand any of the explanations! What is a mash rest? Is it just simply the mashing process itself. If you mash at 160F for 45 minutes. Is that a mash rest of 45 minutes?

I saw a recipe that mentioned
Sacc Rest 15 min @ 143
Sacch II 60 min @ 149
Sacch III 5 min @ 156

What does this mean? And what is "sacc" etc?

I hope someone can clear this up for me.

Thanks!

 

[passedpawn]

Yes, that's all it is. A rest is just the time you leave the mash at a specific temperature.

Traditional brewers did various rests to develop different things in the mash. pH rest, protein rest, and saccharification rests are the ones I'm familiar with. The only rest that is important with 99% of the grains available today is the sacc rest.

The sacc rest is at temps that are optimal for the enzymes to break down large starch molecules into small sugar molecules, makiing them soluble and digestible by the yeast. There are two types of enzymes at work here (alpha and beta), and each type has it's optimal temp. That's why your recipe there shows multiple sacc rests. Typically, we don't mess with 3 different sacc rests. A good compromise is something in the low 150s, for an hour. This is in the working range of both types of enzymes.

BTW, the enzymes and starches both come bound inside that little barley kernel. By milling and mixing with water, we get the party started.

 

[biochemedic]

Rest is any time frame you hold the mash at a given temp. Usually refers to various steps in a decoction mash, or if you have a direct heated mash, the mash can be raised through various temps.

I would assume "sacc" would refer to "saccharification" rest, which most of us single infusion brewers would just refer to as "the mash," as we're pretty much just doing one rest.

I'll leave it to one of the more advanced all grain brewers to try and explain the mash schedule listed in your post...for the life of me I'm not sure why you would step from 143 to 149 to 156*F... AFAIK, 143 and 149 are both in the alpha amylase range, and 156 would be a good rest/mash temp for a more full bodied beer and would favor beta amylase more...

 

[Glynn]

Some brewers like to do staged rests at different times and different temps. its called step mashing. below is a link if you want to read more

Step Mashing
A mashing method that uses multiple steps of temperature, or ranges of temperature, to facilitate the mashing process. It is a somewhat holistic approach, intending to slowly achieve a transformation of the sugars into their most yeast friendly formats. The theory is that by slower heating, the conversions will be able to heat and thoroughly work through to completion before the next step in the mash takes place. This method takes longer, and usually is formed out of five steps, or temperature ranges, but these ranges also correspond with pH ranges for the various Rests: Alpha amylase, beta amylase, ideal mash temperature, glucanase, and protein rest. This method of mashing is the most time consuming, and requires a close attention to the temperature range and the pH of the wort. Most grains used in homebrewing are well modified and usually do not require these additional rests for proper starch conversion.

http://www.homebrewing.com/articles/mashing-methods.php