Trying to understand PM

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waterse

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I was reading a huge post started by Richbrewer a while back about doing partial mashing in a small cooler and I had a question about it. I posted in a new thead as I was reluctant to dig up such a large older post. Anyhow, I was wondering how my steeping method differs from the partial mash technique and what benefit the latter would gain. Currently I steep my specialty grains in a grain bag in 2 gals of water at 155 for 45 minutes, stirring regularly to keep the temp even. I drain the grain bag in a colander and then pour 2 qts of water heated to 170 from a teakettle slowly over the bag in the collander. I allow this to drain fully then proceed to the rest of the steps for extract brewing. So what more does the partial mash technique do?
 
Honestly, it is not much different than this. What differs is that in a PM, small changes in temperature or the thickness of the mash (i.e. the grain to water ratio) does affect the outcome, because these factors directly relate to the activity of the enzymes in the grains that convert starches to sugars. So, your steeping technique should work fine for PM mashing, too -- but you just have to exercise a bit of extra attention to maintaining an appropriate temp (varies with the recipe) and perhaps lower your water to grain ratio.

Sparging technique will also affect the amount of fermentables extracted, which is often more of a concern with PM/AG brewing, but honestly it is no more of an issue for PM brews than steeping.

Cheers! :mug:
 
The physical process doesn't really differ, but what happens at a biochemical level does. When you steep speciality grain, you are only extracting color and flavor (much like a giant tea bag). Mashing involves using a small portion of base grain (like 2-row or Maris Otter, for example) that must be held at a specific temperature in order for enzymes to convert starches into sugars. Most PM recipes that I've used involve approximately 4 lbs of grain (both base and speciality), and DME provides the remainder of the fermentables.
 
Mostly everything was touched on already. The one thing you'd do differently is either use a little more grain (including some kind of base grain like 2-row, vienna, munich or pils) or cut back big time on the water volume. Example:

5 pounds of grain (4 lbs 2-row, 1/2 pound crystal 40L, 1/2 pound carapils for example)
Mash that in 1.5 gallons of water (water to grain ratio is 1.25 quarts per pound) and hold at 152F for 60 mins.
Drain wort.
Re-dunk that grain bag into fresh 175F water (1-2 gallons) and let that drain.
 
So what is lacking is not just technique but a grain that actually produces fermetable sugar. I think I am starting to get it. Partial mash the next batch for sure. Thanks!
 
So what is lacking is not just technique but a grain that actually produces fermetable sugar. I think I am starting to get it. Partial mash the next batch for sure. Thanks!
Right -- essentially a partial mash is a particular type of steeping, except that it is aimed at grainbills that contain starchy grain types, rather than highly kilned grains (caramel/crystal, roast barley, black patent, etc.) that lack starches. If performed correctly, the mashing process will facilitate the natural enzyme activity in the grains so that the starches are converted to sugars that can be fermented.

Typical grains that require mashing (PM or AG) are base malts (such as 2-row, 6-row, British pale ale malt, etc.), Munich, Vienna, malted wheat or rye, etc. If you need to use adjuncts, like corn or oats, you can mix them with a base malt and use the enzymes from those grains to convert the adjuncts.

So the choice of steeping vs. PM brewing basically comes down to whether your recipe contains items that require starch conversion. The Wiki is a good source of info on this:
https://www.homebrewtalk.com/wiki/index.php/Malts_Chart

Hope that helps! :mug:
 
For like 30$ you can make a 5gallon rubbermaid cooler mash tun that works like a champ. No steeping bags involved. You also get the ability to mash 12-13 lbs of grain if need be. Also try playing around with some of the free brew software demos like beersmith or promash. Thats how I got started anyway. 1 PM was all it took to go AG.

https://www.homebrewtalk.com/showthread.php?t=23008
 

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