Help interpreting my partial BIAB methods.

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h4rdluck

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I have been brewing this way for about 6-7 years. My local home brew club thinks I am a little crazy as I just make up recipies and I do a mix of BIAB and Extract brewing. I just don't seem to want to bother going to all grain due to buying more equipment plus I have been doing it this way for so long.

So I have a 10 gallon kettle. I have a bad that can hold 10-20 pounds of grain. But typically I have anywhere between 4-6 pounds of fermentable 2-row or equivalent that I mash in the bag in about 8 gallons of water for 60-75 minutes. Then I pull the bag out, add 3-4 pounds of DME and go to boil and then add the remainder of my DME at flameout basically allowing it to boil for 2-3 minutes before cutting off the flames.

I am trying to determine how much fermentable sugar I may be extracting from my BIAB and I have never bothered to try and really figure it out.

My last batch was a 10gallon barleywine.

I had 4 pounds of marris otter and 4 pounds of german pilsner. This was in 8 gallons of water that I mashed starting at 156 in the brew kettle for 70 minutes. At the end of 70 minutes the kettle reads ~147F (and I stir the grains in the bag up every 15-20 minutes). If it matters there was 2 pounds of crystal 70L in the bag as well (I'm not including that there are always 1-3 pounds of non fermentables in the mash as well - crystal, carapils, chocolate, black malt ect

After this last round I measured the wort after the mash and got a SG of 1032.

What are the effects of having too much water to grains ratio? Am I extracting more or less sugar? Is the mashing efficient? or are the enzymes too dilute to work effectively in conversion?

I then added 15 pounds of DME to the brew (5 to boil with hops) and then 10 at flame out.

My final OG is around 1.1 with all the DME added.

I have beer smith but find it isn't very useful in interpreting my results.

I prefer to just make beer, but I guess lately am looking to know more about my brew technique.

Also since my kettle is 10 gallons only, I have to boil/mash in 8 gallons. Then at flameout I add 2 gallons of water to reach my 10 gallons (I don't want to buy a 15 gallon pot...so I have to dilute at the end as well).
 
I am trying to determine how much fermentable sugar I may be extracting from my BIAB and I have never bothered to try and really figure it out.

The fermentability of your wort is going to depend on a number of factors including mash temp, recipe, yeast strain, etc. and you won't know it until after fermentation. For recipe formulation most folks focus on determining their efficiency, so they know how much grain or extract to use to achieve the correct OG. If your pre boil wort was stirred/uniform, and the reading was 1.032 then you can calculate your efficiency based on how much volume you have. I'd assume with BIAB about a .8 gal absoprtion with 10 lbs grain (you need to include the specialty grains here - they are actually not completely unfermentable, and certainly contribute to OG). That would be 7.2 gals of 1.032 wort or so. With 10 lb grain that's about 64% if my quick calculations are right.

If you are maxing out your kettle but want to go all grain without more equipment you could probably achieve that by dunk sparging in another vessel like a bucket (or pour over sparging if you have a pulley or other way to suspend grain, I find the dunk sparge easier and get better efficiency that way). But if you're happy with your method and results I don't see a reason to change.
 
Thanks for taking the time to calculate that. I guess there may just be too many variables in my method to really get anything very scientific going. But I don't mind to much in the long run. I enjoy the mashing and have better tasting beers than any previous steeping for 30 seconds that most extract recipies I followed very long ago called for.

I also find it easier to keep a 50 pound bag of extract on hand. It takes up very little room. Stays good for a long period of time and in bulk I find it isn't that much more expensive and the ease it imparts to my brewing and need for less equipment is also very important.
 
I think you could get this dialed in if you really wanted to. Sounds like you've got your process down and it's working for you, though. If keeping the DME on hand and then adjusting after the mash is simple for you I don't see a reason to change, despite what your buddies might think. Partial mash is a popular and perfectly good way to make beer, especially if your pot is a little small for the finished batch size you want to make. IMO, with partial mashing BIAB is definitely the way to go.
:mug:
 
For 10 lbs of grain, and 8 gal of strike water, SG of the wort in the mash should be about 1.042 if you got 100% conversion efficiency. Since you only got 1.032, that puts you at about 76% conversion efficiency. Assuming the same 0.08 gal/lb grain absorption that @chickypad assumed, your lauter efficiency was about 85%, and your mash efficiency (conversion efficiency times lauter efficiency) was about 64 - 65%, which is in line with what chickypad estimated (we use completely different methods for calculation.)

Brew on :mug:
 
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