BIAB All Grain Partial Boil? Anyone do this?

[Davrosh]

Does anyone on these forums do or have experience with BIAB all grain partial boils?

I have been doing BIAB Partial mashes for a few months now, and last night I came to the realisation that I could probably ditch the tin of extract that I have been including in each brew, and just up the grain bill.

I only have a 20L(ish) brew pot so I have been doing partial boil partial mashes anyway, using the BrewPal iPhone app to great success (not sure how accurate my calculations are but the beer is tasting good and pretty much what I'm aiming for each time). Typically my grain bill is around 2-3kg (plus a 1.5kg tin of Brewpacks Pale Malt Extract). I use however much strike water the app tells me to mash with. plus as much as I can to dunk sparge the bag afterwards (I have a 7.5L pot which I use for the sparge water, poured into my fermenter to dunk the grain bag in - not ideal but it seems to do the trick). I boil whatever amount of wort I end up with, plus the extract, then top up with water to 23L in the fermenter.

My efficiency seems to be surprisingly high (consistently high 80%s), and I have got to a stage where the BrewPal app is getting the OG pretty much bang on, after several settings tweaks.

So... bearing my method and equipment in mind, am I right in thinking there would be little difference to my technique if I simply upped the grain bill, upped the strike water, and cut the extract out? I suppose the main issue would be that the calculations I were previously using would be somewhat irrelevant?

I know there will obviously be some trial and error in this, so I was thinking of doing a very simple Pale Ale recipe so that I can easier judge what needs tweaking. Something along the lines of this:

23L

4kg Maris Otter
0.25kg Torrified Wheat

25g First Gold (9.8%) 60 mins
15g First Gold 15 mins
10g First Gold 10 mins
10g First Gold 5 mins

Dry hopped with 35g First Gold

Safale S-04


Using BrewPal based on 80% efficiency, im estimating around about 1.047 OG, ~40 IBU. I would expect any deviance either way on the OG should not be too detrimental to the balance of the beer. Does this seem about right (especially to anyone with prior experience of this technique)?

Any advice would be greatly appreciated.

 

[TopherM]

You would follow the same exact process you are using, just replace your LME with the equivilent amount of grain. Everything else would be the same as a partial mash, assuming all of the grain and enough water to mash in fit in your 20L pot.

A 6 gallon pot can cost as little as $30.00 if you go aluminum or about $60.00 stainless steel. It might be time to invest in a larger pot!

 

[wilserbrewer]

Go ahead and try it, be aware that efficiency will drop as the wort increases in gravity due to the partial boil. There was a thread recently about someone doing exactly what your proposing.

 

[Davrosh]

You would follow the same exact process you are using, just replace your LME with the equivilent amount of grain. Everything else would be the same as a partial mash, assuming all of the grain and enough water to mash in fit in your 20L pot.

A 6 gallon pot can cost as little as $30.00 if you go aluminum or about $60.00 stainless steel. It might be time to invest in a larger pot!

I'm Pretty sure I could fit enough grain and water to mash in my pot for a standard gravity brew. Not sure my Electric stove would handle a bigger pot though - takes ages to get boiling as it is. I actually spent quite a while looking for a slightly bigger one before I bought my 20L pot, but it seems they are like rocking horse **** in the UK, unless you want to spend a hell of a lot of cash (which kind of defeats the purpose in why I started brewing anyway).

Cheers anyways.

 

[dcp27]

So... bearing my method and equipment in mind, am I right in thinking there would be little difference to my technique if I simply upped the grain bill, upped the strike water, and cut the extract out? .

thats pretty much it. i used to do it pretty often before i eventually got a bigger pot. it certainly will make due til you are able to handle larger boils.

 

[william_shakes_beer]

Just do a makeup calculation at the start of the boil to see what your OG will be once you add the top off water, and drop some extract into the boil if needed to hit your target OG. I always keep DME in the kitchen to do starters. The calc works something like this:

TV = target volume after topoff
CV = current volume
TG = target gravity after topoff
CG = current gravity
CS = current sugar
TS= target sugar

TS=TG*TV
CS=CG*CV
TS-CS=Makeup with extract.
Makeup is 42 points per pound or DME or 38 points per pound for LME.

 

[Brad1775]

I usually just take the recipe I want, and use it as directed in my 5 gallon SS kettle. I double batch sparge to get all the sugars out, but only sparge with enough water to get it to 4-4.5 gallons. I top off with spring water in the fermentor. I've hit my gravity with this method 4 out of 4 times I've done all grain. The key is a really fine crush, beyond double crushed, I hand mill it at the LHBS

 

[Davrosh]

I usually just take the recipe I want, and use it as directed in my 5 gallon SS kettle. I double batch sparge to get all the sugars out, but only sparge with enough water to get it to 4-4.5 gallons. I top off with spring water in the fermentor. I've hit my gravity with this method 4 out of 4 times I've done all grain. The key is a really fine crush, beyond double crushed, I hand mill it at the LHBS

So it works pretty well then. Just out of interest, what is your efficiency on average using this method? Also, do you up your hops to compensate for a partial boil? I know this is a separate issue, but I've read allot of contrasting reports regarding hop utilisation in partial boils - In my own experience I have never upped the amount to compensate, and the beer usually comes out pretty much how I intended. Personally I don't think that the difference is as big as some of the beer calculators make out. I'd be interested to hear another partial boilers opinion from experience.

Cheers

 

[beargrylls]

how is this working for you?
i've been thinking of doing something like this except with a mash tun instead of BIAB. I would up the grain bill and only sparge til I got about 4 gallons of high gravity wort, boil that, and then top off with water to get to 5 gallons and the right OG. Kinda want to see if I can cut out the extract as I've got a 2:1 grain to extract ratio already