first BIAB - 3gal in 5gal pot?

I just ordered all the grains for my first BIAB brew - have the 5 gal pot and everything ready, but im concerned that the 5gal pot will be too small for a 3gal batch with 7.19lbs of grains. According to calculators i'm looking at needing a bigger pot for this. If i do a small sparge, think i will still be okay with my efficiency? Worst comes to worst, i'll just scale down to 2.5 gal and should be okay

When I BIAB in a 5gal kettle, I typically use 14qt of water and 7.5 to 8 lb of grain, and I have no problem. Typically lose about 3qt to the grains and wind up with about 11qt of wort pre-boil. (I do not sparge, I just let the bag drip through a fine mesh colander with only light squeezing).

(I often do PM BIAB with some extract, but I sometimes do full 5 gal batches by doing two BIAB "halvsies," fridge the first half overnight and use it to rapid-cool the second half...but that's maybe another topic!)

What kind of efficiency and attenuability are you expecting? Mash pH and temperature targets? In a typical 1.050-1.070 OG beer with largely base grains, and keeping my mash pH in a 5.3-5.5 range--and grinding my grains nice and fine!--I can predictably get from 55% to 75% brewhouse efficiency (and similarly, predictable attenuability from the grain portion from 60% to 90%), solely depending on the mash temp.

OG for this beer is 1.066 with 75% eff and 72% attenuation.

i expect my efficiency to be a bit lower probably around 70 since this will be my first BIAB, but hoping to get close numbers.

If i mash at 152 with the 14qt's as you do, i should expect a small sparge to get me to about 4 gal pre-boil. I'm just worried that will effect my numbers. Sounds like it might be beneficial to drop it down to a 2.5 gal batch.

A 70-75% efficiency sounds very doable at that mash temp. What's your grain bill? And are you going to do anything to target a particular mash pH?

I think you'll have a hard time keeping attenuability as low as 72%...though I suppose it will depend on things like the grain bill, mash pH and yeast you plan to use, and whether maybe you plan to use a lot of unfermentable adjuncts (maltodextrin, etc.). By chance is 72% attenuability what you are used to seeing from extract? In my experience that's typical of extract, but with mash you can--and likely will--get much higher attenuation, especially at 152°F mash.

What type of beer BTW? Recipe?

agrazela said:

A 70-75% efficiency sounds very doable at that mash temp. What's your grain bill? And are you going to do anything to target a particular mash pH?

I think you'll have a hard time keeping attenuability as low as 72%...though I suppose it will depend on things like the grain bill, mash pH and yeast you plan to use, and whether maybe you plan to use a lot of unfermentable adjuncts (maltodextrin, etc.). By chance is 72% attenuability what you are used to seeing from extract? In my experience that's typical of extract, but with mash you can--and likely will--get much higher attenuation, especially at 152°F mash.

What type of beer BTW? Recipe?

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Its the Zombie Dust clone from the IPA recipe forum scaled down to 3 gal. I think the attenuability was calculated from the website i plugged in the info, it wasn't something that i filled in myself. I'm not too familiar with that when it comes to brewing, same thing with the pH of the mash.

Grain bill is:
5.875lb 2 row
.565 lb munich light 10l
.25 lb carafoam
.25 lb crystal 60
.25 lb melanoidin

what i do when my grain bill/water volume max's out my pot is pull out 1 gal of water, add your bag and grains, add water back to until your at the max level for the pot, hold the remainder at 170f in the oven, remove grains and drain, sparge to meet required pre-boil level and then carry on. i do it on almost all my 10gal BIAB batches and always get 70-75 eff.

I mash my five gallon batches in a five gallon pot (I boil in an 8 gallon pot). I just fill the mash pot as full as I can and keep the rest of the water in the other pot and then dunk sparge. I love the dunk sparge and even if I had a big enough pot to do a full volume mash I would probably still do it this way.

JDGator said:

what i do when my grain bill/water volume max's out my pot is pull out 1 gal of water, add your bag and grains, add water back to until your at the max level for the pot, hold the remainder at 170f in the oven, remove grains and drain, sparge to meet required pre-boil level and then carry on. i do it on almost all my 10gal BIAB batches and always get 70-75 eff.

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That was going to be my plan - i think i will do somethign similar to that and see what numbers i get and adjust from there

In my experience, online calculators and freeware brewing software tend to be conservative on attenuation numbers. For example, they tend to consider crystal malts and such to give little or no fermentable sugars, which is just not true. I'd expect AA% closer to 80-85% with that grain bill and that mash temp (unless your mash pH is way high, for example). Just means you'll likely get lower FG and higher ABV than you expect, not such a bad thing in an IPA!

What kind of water are you using? And yeast?

I mash and boil in a 5 gallon pot. I dunk sparge, rinse and squeeze the grain in/over a second 3 gallon pot. Then I add the contents of the 3 gallon pot to the 5 gallon pot (which still has the "first runnings"). At this point the 5 gallon pot is nearly completely full and you got to be very diligent and keep a squirt bottle handy until hot break passes.

Using this method I usually get nearly 4 gallons into the fermenter (14.5 - 15 litres).

agrazela said:

In my experience, online calculators and freeware brewing software tend to be conservative on attenuation numbers. For example, they tend to consider crystal malts and such to give little or no fermentable sugars, which is just not true. I'd expect AA% closer to 80-85% with that grain bill and that mash temp (unless your mash pH is way high, for example). Just means you'll likely get lower FG and higher ABV than you expect, not such a bad thing in an IPA!

What kind of water are you using? And yeast?

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Yeast is S-04 - water is just my local tap water, seems to always work well when i'm brewing

As above, I mash then dunk sparge. With caution, I've done 5gallon batches in a 5gal pot. Start your boil with 4gal, add the sparge product after the hot break. Reserve some to top off as it boils down. This lets me boil 4.5 til the end, I then top off with water in the fermenter. So, yes, you can do three gallons in a five gallon pot.