# Converting All Grain to Partial Mash

### Help Support Homebrew Talk:

#### Dextersmom

##### Well-Known Member
Can someone explain to me (like I'm 5) how to convert an all grain to a partial mash recipe?

I've read this article, but with the example I'm trying it leaves me with a ton of DME (like upwards of 12lbs)
http://byo.com/grains/item/2543-converting-to-partial-mash

In every case it says to keep specialty grain amounts then add the base malt up to your mash size in lbs...I wanna do a 4 maybe 5 lb mash so I'll be doing a 2 - 3 gallon volume. but then the explanation looses me. after reaching (lets say 4 lbs) i still have 12.3 of base malt left. it says to multiply that by the potential extract of that type of malt (so now i have 12.76ish). then divide that by the potential extract of the malt extract (leaves me with 12.21)....thats HUGE. I don't think i've ever done more than 8 in an extract batch not counting specialty grains.

does this sound right to anyone?

##### lupulin shift victim
after reaching (lets say 4 lbs) i still have 12.3 of base malt left. it says to multiply that by the potential extract of that type of malt (so now i have 12.76ish) multiplied by the mash efficiency. then divide that by the potential extract of the malt extract (leaves me with 12.21)
I think your calculation is leaving out the important factor of efficiency. No one gets 100% of the potential from the grain so it should read as above. The typical quick conversion factor is 1 lb grain = .75 lb LME = .6 lb DME if you assume base grain has about 36 ppg, LME also 36 ppg, DME 45 ppg, with an average of 75% efficiency.

Or long hand, for 12 lbs of base malt with 36 ppg and 75 % efficiency you have:

(12 * 36 * .75)/36 = 9 lb LME
(12 * 36 *.75)/45 = 7.2 lb DME

OP

#### Dextersmom

##### Well-Known Member
Awesome! The quick convert makes things seem much more normal... I'll either need to really figure this out or just change over to all grain lol.

##### lupulin shift victim
Unless your efficiency is way off or you are using a large portion of base malt with a low potential (a roggenbier maybe) the quick conversion will get you close enough. You can try software, but I was never satisfied with the way Beersmith converts between extract/PM/AG so I do it by hand.

#### ZebulonBrewer

##### Well-Known Member
When I make my recipes into partial mash recipes, don't focus on the exact conversion. Focus on the OG and the specialty grain/color. You find out what kind of efficiency you get over a batch or three, and make adjustments.

Before I moved (throwing my setup into disarray!) I started with 65% efficiency, and in about 6 months I was reliably getting 72%, Consistency is key! (wheat beers not included, those are generally a little lower)

One thing I also suggest is planning your extract around what you can buy efficiently AND fit into your kettle. If I can get away with extract in 3 lb increments (for DME), I will, because it's more economical to buy the full 3 lb bag. Higher OG or really dark beers might need 6 lbs because I only have limited room in my mash for grain (for me it's like 5 lbs grain max)

OP

#### Dextersmom

##### Well-Known Member
Thanks for the input guys... I like the way a quick convert looks and will prolly do it that way today.

Thanks!

OP

#### Dextersmom

##### Well-Known Member
Also I just rounded my amounts so I'm only using 3# increments of dme. I'll tweak it for later batches... This is a recipe I wanna kinda make as my year round go to brew. Designed myself from an all grain that looked to be the character I'm looking for. Then tweaked hops for lots of citrus notes.

#### Yooper

##### Ale's What Cures You!
Staff member
Mod
Also I just rounded my amounts so I'm only using 3# increments of dme. I'll tweak it for later batches... This is a recipe I wanna kinda make as my year round go to brew. Designed myself from an all grain that looked to be the character I'm looking for. Then tweaked hops for lots of citrus notes.
If you want to post the conversion you came up with for us to take a look at to make sure it's going to work, we'd be glad to do that if you're not 100% confident about it.

OP

#### Dextersmom

##### Well-Known Member
Going with the recommendation from BYO that said to keep all specialty grains the same I used this grain bill...

13.5 2-row pale malt
1.4 carapils malt
1.4 crystal malt

decided i was going to do a 5# mash (but rounded up the amounts so i'm slightly higher than 5#)
2.5 2-row
1.5 carapils
1.5 crystal

using the quick estimate of the non rounded amounts I got (11.3 * 36 * .75) / 45 = 6.78 (DME)

so since I like keeping things simple and rounded up already for grain amounts, I just decided to keep my DME at 6#

in the end my purchase was
Grains:
2.5 2-row
1.5 carapils
1.5 crystal

6 DME

Thoughts?

##### lupulin shift victim
11 lbs 2 row should equate to about 6.6 lb DME so the calculations look about right. I'm wondering on the recipe though, that's over 17% cara/crystal which is more than I would put in anything. That's a fairly big grainbill if this is 5 gal, is this an IPA? Even more reason to be careful with too much crystal IMO, I would cut it to more like 5% total. It's also not bad idea in general to have at least half your partial mash be base malt so you have enough diastatic power. I know crystal doesn't need converting but I would still worry about diluting the enzymes on a larger mash with not much base.

OP

#### Dextersmom

##### Well-Known Member
Yeah its an IPA. the crystal i'm using is 10degree. Edit: probably could have kept the specialty grain where they were and used the rest for the base malt, but would .1 off of each of the specialties really make that much of a difference?

can ya explain what you're last couple of sentences mean? lol

##### lupulin shift victim
Well it's up to you but if I were brewing it I'd do something like 5% of the C-10 (i.e. less than a lb) and drop the carapils.

Do you know the concept of diastatic power? Basically its the enzymatic power of the base malts to convert the starches in the mash into sugars. If you don't have enough diastatic power the mash may not fully convert. Some malts have more and can convert themselves plus a significant amount of other grain, some malts can only convert themselves, some malts and unmalted grains have no diastatic power. This article explains it a little better and tells you how you can calculate the diastatic power of your mash.

OP

#### Dextersmom

##### Well-Known Member
The lesson I learned from this: In my slow transition to all grain, I'm going to have to learn more about the real science rather than *POW* ingredients into a kettle. I'll see how this batch goes then go from there. I appreciate all the help, and will check out that link you sent me - start reading up more about it (also open up those chapters in palmer's about all grain brewing). Once I'm done with PA school I'll have more time (one would hope) to concentrate on brewing. Getting a kegging system was the best thing for me b/c I've once again caught the brewing bug which was stomped on by the bottling process.

Thanks guys!