Partial mash questions

I've done 7-8 partial mash brews now, and I still don't completely understand everything about the process. My beers are turning out great, but I'd like to improve my knowledge of the process. I've read DeathBrewer's thread that's stickied to the top of the forum, as well as several other threads I found through the search.

All my recipes come from my LHBS with the following instructions:
1. Heat water to 160F
2. Add all grains (base + specialty are pre-mixed, usually 4-6 lbs IIRC)
3. Maintain ~155F for 1 hour
4. Lift grains completely out of mash and set in a metal strainer above the kettle
5. Pour 170F water over grains
6. Let grains completely drain (10-15 mins) and then discard
7. Heat to boiling, add extract, proceed with boil

I follow these instructions word-for-word, but I'm not sure this is necessarily the best method, because I notice a lot of people doing different variations on these forums. I know the point of mashing - to allow enzymes to convert the starch in the base grains to fermentable sugar. I understand the boil - to allow the hops to release AAs and aromatic oils that contribute to the bitterness, flavor, and aroma of the beer.

What I'm struggling with is the role of the specialty grains. My understanding is that they are only there to contribute flavor, so you steep them at a higher temp than the mash to release this flavor from the grain. Makes sense. What I don't understand is where this steeping process comes into play in the directions provided by my LHBS. I'm assuming they are steeping during the 1-hour mash at 155F. Is that correct? Is this the optimal temperature for steeping, or is it largely dependent on the type of specialty grain?

I'm also a little confused about the sparging process. Is the purpose of this to simply remove the last little bit of sugar from the grains? My instructions call for a single pour of 170F water, but in DeathBrewer's thread, he actually transfers the grain bag to a separate stock pot containing 2 gallons of 175F sparge water, and soaks the grain for 10 minutes. That seems like it would be better, just because it allows more time to get sugar out. Is that correct?

Sorry if this was long and redundant, but I've done searches and read in a couple books and I still haven't found clear answers to my questions.

Well, im just about to brew my first partial saturday and i too have directions from austinhomebrew.com that look very similar to yours and have too been using deathbrewers stickied thread to trouble shoot.

For the sparge my recipe says 1quart water/2lbs grain heat to 170f and pour over grain - than add a gallon to your kettle before you do your boil. I have 3.5 pounds of grain so that would be 1.5 quarts of water + 1 gallon = 1gallon 6 cups sparge water

i personally plan on sparging in 170f in a separate pot filled with 1.5 gallons (slightly more than what the ratio of grain/water is according to my recipe and slightly less than deathbrewers method - this would mean i would be boiling 3.5 gallons)

i believe it will work fine that way.

i would imagine longer sparge time is the way to go to really get all the sugars out of your grain.

im personally scratching my head as to why my recipe is telling me to pitch my yeast at 80degrees - that just seems way to hot - i would assume pitching yeast around 67-70 would be ideal.

sorry i couldnt be more of a help but maybe the method i used will help you blend your different instructions together.

The techniques get a little complicated but it's really a simple process. At a certain temperature or set of temperatures, enzymes activate to help convert your base grains' starches to sugars. After that conversion is complete, you want to separate those sugars from the grains and start your boil. That's all there is to it. Everything else is just a matter of efficiency.

Specialty grains don't have to be mashed. All that needs to be done there is to strip the grains of the sugars and whatever other flavor-related properties are in the specialty grains.

We separate the sugars from both the already-mashed base grain and the no-mash-need specialty grains by rinsing with hot water. We use hot water because it's better at getting sugar into solution than cold water. (Just take a look at how hard it is to stir sugar into ice tea versus coffee for an example of that.) The hotter the better at getting sugars out but too hot and you start to break down the grain husks, resulting in tannins. That's why 170F is a popular temp. It's almost as hot as you can get without extracting tannins. You can do it an any temp you want, but too hot and you get tannins. Too cold and you lose efficiency.

So with the DeathBrewer method (and most other batch sparge methods), specialty grains are just along for the ride in the mash (which has to be in a certain temp range for conversion of base grains). The original mash water is separated from the grains. Then those grains are soaked in water that's as hot as you can get it without negatively impacting the finished product to wash away as many sugars still stuck in the base and specialty grains as possible.

Gotcha. So if I understand you correctly, the mash process simply converts the starch to sugar, but the sparge is necessary to completely extract the sugars from the both the base grains and the specialty grains. In other words, if you didn't do the sparge, or if your sparging technique is poor, you would have very low efficiency and probably lose some flavor. Is that correct?

I guess I'm trying to figure out the best way to do the sparge. If I'm pouring 170F water over the grains and allowing it to drain into the kettle, then that means the hot water isn't in contact with the grains for very long. It also means I need to get that water spread evenly over all grains, otherwise I might be losing some sugar around the edges. It seems like there is a lot of room for error here.

The DeathBrewer method seems a little more fool-proof and efficient, but it requires that you have a second stock-pot large enough to hold your grain bag. I'm not sure I have that at the moment, but if I do, I might start doing this method from now on.

drycreek said:

Gotcha. So if I understand you correctly, the mash process simply converts the starch to sugar, but the sparge is necessary to completely extract the sugars from the both the base grains and the specialty grains. In other words, if you didn't do the sparge, or if your sparging technique is poor, you would have very low efficiency and probably lose some flavor. Is that correct?

I guess I'm trying to figure out the best way to do the sparge. If I'm pouring 170F water over the grains and allowing it to drain into the kettle, then that means the hot water isn't in contact with the grains for very long. It also means I need to get that water spread evenly over all grains, otherwise I might be losing some sugar around the edges. It seems like there is a lot of room for error here.

The DeathBrewer method seems a little more fool-proof and efficient, but it requires that you have a second stock-pot large enough to hold your grain bag. I'm not sure I have that at the moment, but if I do, I might start doing this method from now on.

Click to expand...

Sounds like you understand just fine. Back when I did 5 gallon batches, I did something very similar to DeathBrewer's method with the grain bag but I actually conducted the mash and sparge in a grain bag in a 5 gallon water cooler and dumped the runnings into my kettle. It doesn't have to be a stock pot. You could even use a plastic bucket for the sparge part or to hold the first runnings temporarily while you sparge (which you may have on hand if you're fermenting in one).

drycreek said:

Gotcha. So if I understand you correctly, the mash process simply converts the starch to sugar, but the sparge is necessary to completely extract the sugars from the both the base grains and the specialty grains. In other words, if you didn't do the sparge, or if your sparging technique is poor, you would have very low efficiency and probably lose some flavor. Is that correct?

I guess I'm trying to figure out the best way to do the sparge. If I'm pouring 170F water over the grains and allowing it to drain into the kettle, then that means the hot water isn't in contact with the grains for very long. It also means I need to get that water spread evenly over all grains, otherwise I might be losing some sugar around the edges. It seems like there is a lot of room for error here.

The DeathBrewer method seems a little more fool-proof and efficient, but it requires that you have a second stock-pot large enough to hold your grain bag. I'm not sure I have that at the moment, but if I do, I might start doing this method from now on.

Click to expand...

Truly, it doesn't matter. You sparge to rinse the sugars that may not be in the liquid off of the grain. No need to soak it or anything, although that also works.

Either way works fine, and gets the job done.