Partial Mash Techniques

I've never brewed an AG recipe before because I lack the appropriate tools (mash tun, etc) but I found an AG recipe recently I wanted to try. Fortunately, I found a partial mash version of the same recipe that uses an extract but I have questions about how well it will actually work.

The partial mash recipe basically replaces some of the base grain with LME. It says to combine some of the remaining base grain with the speciality grains (some of which are mash-only) in a bag and heat it in water (first to 144 quickly then to 169 slowly) and to sparge by pouring 170 degree water over the grains in a strainer afterwards into the original container and then boil and proceed as normally.

This seems almost too simple and is pretty different from most of the other methods I've seen out there. I'm wondering if it will work and what are the potential disadvantages to this method.

First, is it a problem that I am boiling the wort in the same container I performed the mash in. Other partial mash directions usually have you prepare a separate container (such as a cooler with a spigot) with a bag of grain, then add hot water, wait, and then drain the wort in to the boiling pot.

I never really understood why you can't just use the boiling pot to mash and simply remove the bag of grain from the pot when you are done mashing. Is the problem due to issues with oxidation of the wort when the bag drips into the pot as it is sparged or removed? Or is a cooler preferred because it keeps a constant temperature without requiring it to sit on a stove?

The recipe also says to add the bag to the cool water, rapidly heat it to 144 then slowly (over 30 min) to 169. I assumed this is because the original AG recipe was a step mash with several rests between 144 to 169. Most of the partial mash recipes I've seen have you add hot water to the grain and let it sit. Is there an issue with mashing while adding heat on a stove?

Finally, it seems that this is truly a partial mash and not just steeping, although sometimes it is hard for me to tell when a recipe is mashing and when it is just steeping specialty grains. I've been told that steeping is very different from mashing since no enzyme activity actually takes place, but a simple partial mash like this both involve soaking a bag of grain in water at around 140-160 degrees for an extended period of time, so I'm wondering what the difference is?

There's a sticky about this technique here. Yes it is very simple. I was surprised at how easy it is when I first tried it about four months ago, but now almost all my beers are partial mash. Read the sticky, there are some slight differences between Deathbrewer's technique and the technique you describe from your recipe. I don't mean to say one is right and one is wrong. After you do it a couple of times you'll arrive at a method that is slightly different from either of them, but works well for you.

I like to use BeerSmith. One feature is it tells you the temperature your water has to be to hit your mash temperatures. Remember your mash is several pounds of grain at room temperature, so simply adding 148F water to it will not bring it to 148F.

Thanks for the link. I think I might try a variation of it for this recipe. It seems a little bit easier than the one in my recipe.

It seems like the downside to DeathBrewers technique (and to some extent the original technique too) is that all of the pouring of hot wort could result in unwanted oxidation of the wort, am I correct?

If I use DeathBrewers technique, I might try converting it to a step mash like the original by adding water at various temperatures to the grain. Will that work? Provided I've calculated the temperature and volume of water needed to hit specific temperatures.

Oxidation at that stage is not an issue. There's actually a little less pouring than a traditional multi-vessel mash; and when you get into things like decoctions there's quite a bit more pouring. Oxidation is really only an issue during and after fermentation.

So if oxidation isn't the issue, why go through all the trouble with mash tuns and lautering tuns and all that? Why not just drop bags of grain in water heated to the appropriate temperatures etc like in the simple guide to partial mashing. What is the downside? It is because it is too hard to do large amounts of grain or full boils?

gio said:

So if oxidation isn't the issue, why go through all the trouble with mash tuns and lautering tuns and all that? Why not just drop bags of grain in water heated to the appropriate temperatures etc like in the simple guide to partial mashing.

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Lots of people do that. Google "Brew in a Bag".

What is the downside? It is because it is too hard to do large amounts of grain or full boils?

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Large amounts of grains are tough, doing a step mash or other complicated mash schedule is tough. I use my brew in a bag setup about 90% of the time and my 3-vessel only for mash schedules other than single-infusion and/or really big beers.

gio said:

So if oxidation isn't the issue, why go through all the trouble with mash tuns and lautering tuns and all that? Why not just drop bags of grain in water heated to the appropriate temperatures etc like in the simple guide to partial mashing. What is the downside? It is because it is too hard to do large amounts of grain or full boils?

Click to expand...

Yep. It's almost impossible for me to get 26 pounds of grain into a bag and then lift it out afterwards. You also want the grain to be "loose" in the bag, and either need several bags or a ginormous bag. My favorite recipe has 26 pounds of grain in 1.5 quarts of water per pound mash ( 9.75 GALLONS of water)! That's not easy in a bag and a pot.

The only point of a mash tun is to have a place to mix the grain and water. The only point of a lauter tun is to seperate the resulting liquid from the grain. If you can do it with a bag, a bucket, a pot, a cooler, etc, then whatever works is fine to use.

So if oxidation isn't the issue, why go through all the trouble with mash tuns and lautering tuns and all that? Why not just drop bags of grain in water heated to the appropriate temperatures etc like in the simple guide to partial mashing. What is the downside? It is because it is too hard to do large amounts of grain or full boils?

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Tradition. Brew-in-a-bag is a new, modern technique. Traditional mashing is thousands of years old. Also, brew-in-a-bag is pretty hard to do with more than 5 gallons. Try lifting a bag with a barrel's worth (or 100 barrels' worth) of damp grain without it tearing.

Thanks again everyone.

I'm trying to figure out the best method to use for this particular recipe. It uses 7.125lb of grain for 5 gallons liquor.

Using 1.25 qt/lb for strike water, that means mash with 8.9qt of water.

And using 2 qt/lib for sparge water, that is an additional 14.25qt of water or 23qt of water. That's a little much for my 24qt pot. So I guess I'm going to have to use DeathBrewer's technique and dip the grain bag into the sparge water instead of attempting to wash it with 14qt of water. Does that make sense?
My fear now is oversparging if I use DeathBrewer's method.

gio said:

Thanks again everyone.

I'm trying to figure out the best method to use for this particular recipe. It uses 7.125lb of grain for 5 gallons liquor.

Using 1.25 qt/lb for strike water, that means mash with 8.9qt of water.

And using 2 qt/lib for sparge water, that is an additional 14.25qt of water or 23qt of water. That's a little much for my 24qt pot. So I guess I'm going to have to use DeathBrewer's technique and dip the grain bag into the sparge water instead of attempting to wash it with 14qt of water. Does that make sense?
My fear now is oversparging if I use DeathBrewer's method.

Click to expand...

If you're "dunking", you really can't oversparge because the pH will be fine. As long as you don't use more than 14.25 quarts of sparge water, you'll have no problems.