What is Partial Mash

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Wrey

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So I am pretty new to brewing although I have been lurking on these boards and doing a good bit of research. I hear alot about extract/PM and All grain.

What exactly is PM brewing?

What are the differences between Extract w/ seeping and PM?

What additional equipment do you need?

How much longer does it take?

What is the advantage over extract brewing?

These are some of the questions that I have had but haven't been able to find clear answers. Does anyone have and good links to this sort of noob information.
 
Partial mashing is also called mini-mashing. There is some info on the wiki: https://www.homebrewtalk.com/wiki/index.php/Partial_Mash_Simplified

Basically, the technique is like steeping specialty grains except that you use some 2-row or other base malt, and there is actually some conversion going on in there. When you steep crystal or other specialty grains, you get color and flavor but not fermentables. Partial mashing allows you to extract some sugar.
 
I'm looking to start PM because I do not have the ability to go AG at the moment due to the limitations of my stove. I'm planning to mash as much grain as possible for all my brews based on a 3 gallon boil, then add extra light DME to make up the fermentables and top off to 5.5 gallons in the fermenter. From everything I have read, this should have a marked effect on the quality of my beer and I am looking forward to the additional control over the process.
 
I just started doing PMs, one under my belt, two and three coming up this weekend, and in my one batch I noticed a marked improvement. That first batch was a hefe and it came out much cleaner than it's extract twin which I'd just brewed weeks before.

For all my future brews, until I make the jump to AG, I'm planning on mashing as much grain as I can which for me is about 6-7lbs. since I can only safely boil around 3.25 gallons of wort.

Yooper answered the "what is it" and "what's the difference" questions so I'll try the next two, equipment and time.

As far as equipment is concerned I invested all of ~$40 in making the switch to PM. A 5 gallon round cooler from Wal-Mart for $17 and misc. plumbing supplies from Home Depot. If I had the link from FlyGuy's sig I'd throw that in here, maybe he'll chime in. I used his parts list to build my MLT and that was it, I was off PMing.

Time wise, I can't say it takes any longer to do PM. I've only done the one but it didn't feel any longer than an extract batch although I wasn't timing it. But seeing as it was my first I imagine it will be my worst timing wise since I'll get better at planning and layout.
 
First off, most of your questions are pretty normal and could have been answered if you'd spent some time searching the forum and reading. I'm not saying that to criticize you, but to point out that there's a lot of good material out there and that it's a great idea to spend some time reading and researching because you'll learn a ton.

It can be done with something as simple as a grain bag in your brew kettle, but personally I am a big fan of the 2-gallon insulated mash tun I built based on this thread:
https://www.homebrewtalk.com/showthread.php?t=19413
(this also has an added bonus that you can later swap the parts directly into a 5-gallon rubbermaid cooler if you want to do bigger partial mashes or even all-grain)

Roterdrache said:
Time wise, I can't say it takes any longer to do PM. I've only done the one but it didn't feel any longer than an extract batch although I wasn't timing it. But seeing as it was my first I imagine it will be my worst timing wise since I'll get better at planning and layout.

Generally speaking, it does take longer than an extract batch - you do the whole mashing process (which can take an hour) before you even start the boil, whereas with a basic extract batch you go straight to the boil. The line blurs a bit if you compare it with an extract batch with steeping grains, which can add a bit more pre-boil time... and with a PM you can sort of overlap the wort collection from mashing with the boil to save a little time (get some water heated in the pot, so when your first and second runnings are collected you're already close to boiling)
Subjectively, I found partial mashing to be a lot of fun and well worth the bit of added time it took.

Of course, as soon as I got a bit more equipment, it became obvious that other than the volumes of grain and water I was dealing with, it really wasn't too much more of a step to just doing all-grain ;) But, if you're equipment-limited, and/or space-limited, partial mashing is a great way to improve your brews and get more flexibility in your recipes (since you have access to a lot more grains)
To expand, the advantage of PM vs. steeping grains is that mashing allows starch conversion which allows you to use all different types of grains, whereas basic steeping only rinses starches/sugars/other compounds from the grains as they are. Only certain grains really work for steeping, such as crystal or roasted malts (which are for color/flavor/body/mouthfeel, not really for getting fermentable sugars), whereas if you mash you have access to way more variety of grains. For example, check out this grain list, which indicates which grains need to be mashed:
http://www.bodensatz.com/staticpages/index.php?page=Grains
and it's pretty obvious that mashing opens up a lot more grain possibilities.
 
So the difference between PM and all grain is that you only mash some of the grains and then fill the rest of the sugar with DME and that you still only do a partial boil?
 
Wrey said:
So the difference between PM and all grain is that you only mash some of the grains and then fill the rest of the sugar with DME and that you still only do a partial boil?

That's pretty much it. With AG you are getting ALL of your fermentable sugars by converting them yourself. With PM, you're only getting SOME of your fermentable sugars by converting them yourself, the rest comes from LME or DME.

As for the partial boils, you can do partial boils with PM and extract with steeping, but you need to do full boils with AG. You can, however, choose to do full boils with PM and extract with steeping if you have the equipment and choose to. It's just an option to consider.:mug:
 
What about cost differences, I am always about saving money if I can.
 
Wrey said:
What about cost differences, I am always about saving money if I can.

In the long run, the cheapest option is all grain brewing. There are, of course, initial start up costs in equipment to get set to do all grain, but your cost per batch for your ingredients will be significantly lower.

As an extract brewer, I was paying between $25-40 to make a batch of beer. I'm now looking at $15-25 to make a batch of beer as an all grain brewer. I'd see even further savings if I bought grains and hops in bulk and crushed the grains myself.
 
Partial mashing can save you a little money, but usually not much. Usually with PM batches I only mash about 3-4 pounds of grain, which can equate to something like 2-2.5 pounds of extract (less if some of what you're mashing is adjuncts which would have otherwise been steeped) which by my LHBS prices ($1/lb for grain and $3.39/lb for extract) means I only save 2 or 3 bucks. The cost savings definitely weren't my main reason for doing PM brews, because although the equipment to do PM batches wasn't extremely expensive, it would still take a long time for it to pay for itself while only saving a couple bucks a batch.
 
I recommend the FlyGuy conversion ... PM will take a bit longer, and it is a bit cheaper, but the results are most clearly worth it..

I think of it like training wheels for AG
 
My LHBS charges $5/lb for DME, but the grain prices are on par at $1/lb. and he'll crush them the night before I brew. My only PM I've done, was 5lbs of grain, and 2lbs of xtra light DME.
Now that I've got a turkey fryer and a wort chiller ordered, I'm going all-grain to cut my costs. if you're gonna PM, and can find a way to boil/cool a 7 gallon pot, AG is where its at.

plus its a lot more interesting to mash grain, than open a can of extract and pour.

*edited to fix a lot of typos as I enjoy a few too many irish reds)
 
So after some additional research and the help from you guys I think I have a better understanding of what mashing is.

I am planning on building a tun today or tomorrow so I can make my next brew with a partial mash.

Some questions that I still have are...

1) What temperature should I keep my mash at. I have read different things, The Joy of HomeBrewing says to keep it at different temps for different times and some things are saying to just let it sit at 165ºF for 45 minutes. Also what is the best way of keep the temp constant, do you have to keep adding hot water to it or can you just let it go.

2) How do I calculate effiency and should I be worried about it. I plan on making the tun from the Wiki with the S/S braid. Along with that how do I know how much DME to add to bring up the SG to where I want it.

3) How do I batch sparge and how much water do I do it with. From my understanding I add 165º water to the lauder tun, let it sit for a few minutes and then drain it to my brew kettle.

4) How can I take a AG recipe and turn it into a PM recipe, or do I have to find a partial mash recipe. Also I am looking for a standard Hefe recipe that I can do.

Thank you again for helping me out.

EDIT: Also, should I get a beer program or are those mostly for AG brewers. Also, anyone have any good links for a step by step PM brew guide, most of the stuff I have found has been more of theory and the basics but not actual step by step stuff.
 
Wrey said:
1) What temperature should I keep my mash at. I have read different things, The Joy of HomeBrewing says to keep it at different temps for different times and some things are saying to just let it sit at 165ºF for 45 minutes. Also what is the best way of keep the temp constant, do you have to keep adding hot water to it or can you just let it go.
It depends on the recipe. Typical mash temps are in the range 150-158F. The temperature affects the finished product because it affects how fermentable the wort you get from mashing will be. I don't have a lot of advice here, but it might not be a bad idea to just shoot for the middle of that range to start with, until you get a feel for your equipment and can accurately hit the right mash temp and be sure you can hold it steady. Be aware that you have to add water that is quite a bit hotter than your target mash temp because of the heat absorbed by the grains and mash tun. You also need to be using a good grain-to-water ratio, usually something like 1.25qt/lb. This is an area where brewing software is REALLY handy.

Wrey said:
2) How do I calculate effiency and should I be worried about it. I plan on making the tun from the Wiki with the S/S braid. Along with that how do I know how much DME to add to bring up the SG to where I want it.
Do some searching for calculating efficiency if you wish, however I do not generally bother worrying about it when doing partial mashes. Since you are only getting part of your wort from mashing, your efficiency won't affect your OG as much as it would with all-grain. As far as how much DME to add, well, I would recommend following a pre-written partial mash recipe, or using brewing software if you want to formulate your own recipe.

Wrey said:
3) How do I batch sparge and how much water do I do it with. From my understanding I add 165º water to the lauder tun, let it sit for a few minutes and then drain it to my brew kettle.
Here I would also recommend you refer to existing recipes and/or use brewing software.

Wrey said:
4) How can I take a AG recipe and turn it into a PM recipe, or do I have to find a partial mash recipe. Also I am looking for a standard Hefe recipe that I can do.
I would not recommend trying to make your own recipes until you are more familiar with the PM process... There are plenty of partial mash recipes out there to get you started (try the beertools.com recipe library). If you want to go making your own, the general idea (if starting with an AG recipe) is to replace some/most of the base malt with DME and use the partial mashing for the specialty grains and maybe some of the base malt - but this is made a whole lot easier with brewing software.

As far as a Hefeweizen recipe... I would suggest, based on my limited personal experience on the matter, that you not try a hefe as your first PM brew, if at all. I made two hefes using partial mash recipes, and was disappointed with both, and then switched to a much simpler pure extract recipe, with no PM, and it turned out a whole lot better. That's not to say you can't make a good hefe with PM (because I'm sure you can), but hefes are really pretty simple, and there are other styles that would probably benefit more from doing a partial mash with specialty grains and would thus probably be better to start with.

Wrey said:
EDIT: Also, should I get a beer program or are those mostly for AG brewers. Also, anyone have any good links for a step by step PM brew guide, most of the stuff I have found has been more of theory and the basics but not actual step by step stuff.
I use the beersmith software and I find it to be a GREAT tool. There's a 21-day free trial, so it wouldn't be a bad idea to check out, and would probably help quite a bit with your current confusion.

As far as a step-by-step guide, well, I don't have any links for you at the moment, but here's a very brief run-down of what I do:
1) put grains into mash tun
2) measure out right amount of water (usually 1.25qt/lb) and heat to the right temperature (calculated with beersmith)
3) add to mash tun, stir, and cover, set a timer for an hour. It should have reached your target mash temp.
4) toward the end of the hour, if I'm getting impatient, I sometimes start pulling small samples of wort and testing with iodine to see if the starches have finished converting to sugars. Some people say "don't bother", but I like being sure.
5) near the end of the hour, measure out your sparge water and heat to the correct temperature (again, I calculate with beersmith)
6) drain some of the wort from the mash tun, pour it back into the top - repeat until it pours relatively clear/free of sediment.
6) open the valve on mash tun, drain all the liquid into the brew kettle.
7) close valve and add sparge water. Let it sit for about 10 mins.
8) open the valve and drain into the brew kettle again.

Now, you've got some wort in your brew kettle, and you just continue on with the rest of your brewing process as you would with extract brewing - add some more water if needed, add extract, etc.

*edit* I did a short writeup of my first partial mash a few months ago, which you might find interesting:
http://eegeek.net/content/view/72/39/
 
So this isn't exactly on topic for the thread but it is my thread so I am going to do what I want with it :p

So I am decided on brewing a extract Hefe and the only night we have to brew is tonight. Problem is I haven't made a starter for the liquid yeast (nor have I even used liquid yeast before)

What are my options for the brew night. We really want to brew tonight.

How would it work if I started the starter right when I got home which would give me about 4 hours till I actually pitched the yeast. Would this be enough time to at least get the yeast hydrated and give them a little oxygen and sugar to get started.

How would it work if I just pitched the liquid yeast directly into my wort. Would I be screwing myself or just increasing the lag time.
 
I wouldn't bother with a starter, if you only have 4 hours. I'd go ahead and pitch it directly. You will probably have a long lag time, but that's the only problem.
 
Go ahead and just pitch it. Just be sure to aerate the heck out of your wort first. Underpitching a hefe might lead to attenuation problems, but probably not if you aerate well. It might also produce more fruity, banana-like esters and spicey notes, but that would be fine in this style of beer.
 
What we did last time was to use the spray hose on the sink to fill the carboy up to the 5 gal limit which made the whole thing aerated as hell.
 
If you dont have time to make a starter, just boil a couple cups of water, let it cool in the fridge, then rehydrate your yeast in that before you boil. By the time your wort is cool and ready for the yeast,
 
Alright, just brewed the Hefe,

The recipe called for 6.5 pounds of LME. I changed it to 7 pounds DME since all the last brews have been a little weak on flavor and ABV.

After brewing we took a SG reading and got 1.032 (oh noes)

But we aerated the crap out of the wort. Will that affect the reading?
 
Wrey said:
Alright, just brewed the Hefe,

The recipe called for 6.5 pounds of LME. I changed it to 7 pounds DME since all the last brews have been a little weak on flavor and ABV.

After brewing we took a SG reading and got 1.032 (oh noes)

But we aerated the crap out of the wort. Will that affect the reading?

Unless you ended up with way more than 5 gallons, or managed to forget to add about half of that extract, there's no way your OG could be that low.

7 lb of DME in 5 gallons should give you an OG of 1.061 or so. I would ask if you perhaps made the common mistake of adding top-off water and taking a SG reading before properly stirring/mixing, but you say you aerated it (presumably by shaking?) before taking the reading?
 
Actually how we aerated it was by filling up to the 5 gallon mark using the hose extension on the sink. This sprayed a butt load of bubbles into the carboy, we had to wait 20 minutes for all the bubbles to settle before we could even take a reading.
 
Wrey said:
Actually how we aerated it was by filling up to the 5 gallon mark using the hose extension on the sink. This sprayed a butt load of bubbles into the carboy, we had to wait 20 minutes for all the bubbles to settle before we could even take a reading.

Well, although I would expect this to have mixed it moderately well, it's still quite possible that this resulted in a layer of mostly water near the surface, resulting in a low OG reading. You should always stir it really well, and/or put the lid on and shake it for a bit, before trying to take an OG reading.
 
evandude said:
Well, although I would expect this to have mixed it moderately well, it's still quite possible that this resulted in a layer of mostly water near the surface, resulting in a low OG reading. You should always stir it really well, and/or put the lid on and shake it for a bit, before trying to take an OG reading.

That's why I pretty much quit taking O.G. readings on my extract brews. I got such a variance that it didn't make any sense. I'm sure it was because the wort wasn't thoroughly mixed. An O.G. on an extract brew is really not necessary and usually leads to worrying.
 
IowaStateFan said:
That's why I pretty much quit taking O.G. readings on my extract brews. I got such a variance that it didn't make any sense. I'm sure it was because the wort wasn't thoroughly mixed. An O.G. on an extract brew is really not necessary and usually leads to worrying.
Agreed. I've taken OG readings on less than half of my extract brews, especially after the first few... The only time I would really want to take an OG reading on an extract brew would be if I made last-minute changes to the recipe without measuring (maybe realized too late that my bag of DME had less in it than I thought, or maybe just threw some extra in 'just for good measure' without weighing it), but if starting from a recipe and following it pretty well, there's not much point.
 
I did kinda change the recipe. I was making "the witch's brew" which calls for

4 oz. German Munich Malt
6.5# wheat malt syrup
1 oz German Hallertau (60 minutes)


I changed it to

4 oz German Munich Malt (I didn't have a scale so I put in 1/4 of a 1 pound bag)
7# Wheat Dry Malt Extract
1 oz Hallertau (60) minutes
1 oz Halleratu (10) minutes

Hopefully it turns out alright.
 
I've seen some references to this BYO article:
http://byo.com/feature/1536.html

In it he just uses a grain bag, and no false bottom. What is the consensus on this process? Is the false bottom a better method? Or is this pretty much left to personal preference?
 
Well as long as you know how much DME you put in with some accuracy, you can just stick your recipe in some brewing software and get an accurate enough OG. Beersmith has a free trial, beertools.com has a free online one, and I'm sure there's others. I'd do it for you in beersmith if I was at home...
 
So I got a new question now, (thanks Even BTW for being responsive)

I take a look at my carboy (this is the first time we have used a glass carboy as a primary) and it is clear that the yeast hasn't really started yet (no bubbling or anything) but there is still a 1/2 inch thick layer of stuff at the bottom. The only thing that I could think it was is the malt extract that has settled out of the wort.
 
I guess I have one last question, what temp should I let the hefe ferment at
 
higher temps (70-73) will in theory give more esters (fruity) notes. If you like styles that have that (Pyramid, for example) then go that route. Otherwise, stick to 65-68. That's my direct experience on Hefes, which I love. I'd love to hear others on this who know way more than me.
 
I found a thread with hefe temps, too lazy to link, le cry
 
I made two hefes, both of which fermented in the 65-68 range with WLP300 yeast. Neither of them had very much hefe character, which was disappointing. My third was fermented at around 69-72 and had plenty of hefe character, especially banana. I also changed my recipe along the way though, so take my experiences with a grain of salt.

By the way, go look at homebrewer_99's recipe and advice, I consider him a hefe guru and he was largely responsible for my third hefe turning out as good as it did :)
 
kappclark said:
I recommend the FlyGuy conversion ... PM will take a bit longer, and it is a bit cheaper, but the results are most clearly worth it..

I think of it like training wheels for AG

Definitely. It is worth the cost of the cooler and the few parts to convert it because it is way easier to work with than trying to control the temp with the stove and strain out the wort without getting any husk in there. Trust me that's just a hassle! The FlyGuy MLT is awesome for partial mashing and IMO the best solution for people who brew in a limited space such as their kitchen.
 
Again this isn't really on topic for the thread but darn it... I started it so I can hijack it.

So I brewed a Hefe on 8/15/07 (6 days ago now) and if you put your nose near the airlock it smells pretty darn bad.

The last couple of batchs after a day or two they smelled like beer. There is still airlock activity and krusen (sp?) on there.

Do you think I have an infection. I could also post a pic when I get home.
 
It's hard to judge by smell alone, some beers just smell yucky when fermenting. A hefe can have some funky smells but if it looks like beer and tastes like beer you're good to go. Might grab a sample and give it a taste. If it has an infection it'll probably taste sour.
 
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