Consistently Missing The Mark

[notixx]

Hey there guys.

I'm a new brewer doing 1 gallon BIAB batches currently.
I brew once a week currently, testing different strategies, recipes and techniques. I'm going to refine my process for awhile still before scaling up to 3 gallon batches eventually.

The first couple batches, i was hitting my OG right on. Every time seemed to come out right on.

The last three batches, i've consistently ended up with a low OG. Usually attempting to reach around 1.055 and ending with 1.041-1.045 instead

I'm just looking for small hacks/tips from other BIAB brewers. What do you do to hit the mark every time? when you dont make the mark, what's usually the culprit?

 

[s1080]

When mash inefficiencies arise a number of things can be the culprit. I assume you are using the exact same method.

First, are you using city water or bottled? When using city water changes to it's chemistry can happen thus changing the effectiveness of your mash.

Second, is it the same recipe? The types of grain you use can actually change the chemistry of the mash thus lowering your efficiency as well. What I mean is that the mash chemistry of a stout is going to be different then a pale ale.

Third, are you grains always coming from the same source and are they fresh? Sometimes grain, when improperly stored, can result in different mash efficiencies.

 

[notixx]

1) Using well water from tap.

2) Not the same recipe. I assume that could be the issue somewhat, however I have brewed similar recipes with different results

3) I use grain from my LHBS. He is a homebrewer as well and i'm sure he mills the grain quite consistently and properly stores it

 

[s1080]

hmmm... What is your BIAB method if you don't mind me asking?

 

[Homercidal]

There are a few things. The amount of grain needed for a recipe will change. More grain needs more water because more water will be left in the grain after lautering.

Grain crush can impact efficiency. A finer crush will result in a higher efficiency with the downside being the possibility of a stuck sparge. Since you are BIAB the chances of that are near nil.

Water chemistry can affect pH, which can affect the ability of the enzymes to convert the starches in grain to sugars that the yeast can eat.

Any of these seem likely?

 

[notixx]

I do a mash with 1.5 quarts of water per lb of grain
after mash out, i pull the grain bag above the kettle and let it drain in a strainer, sparge with enough 170 degree water to get to 2 gallons by pouring it evenly over the grain bag in the strainer.

After the boil i'm left with my 1 gal batch

 

[notixx]

i usually do squeeze the bag as well to help with efficiency

 

[oakbarn]

It seems to me you are trying to find an error in your process (efficiency) but changing more than one variable at a time. My brew partner is always telling me not to change more than one thing when we are trying to get the process down. We do much larger batches and also normal batch sparges and have never done BIAB but the "process" of getting down your process is the same regardless of what widget you are using.

We have found that we cannot "exactly" produce the same OG with the same grain purchased from the same source using the same grain mill, but we are very close. We use the dilution method to get the correct OG (change the final volume with the addition of water). We overshoot on purpose and normally will have to add water near the end of the boil. Of course in a small batch such as yours, the Volume difference would be to much a delta (we do 25 gallons so a 24.5 to 25.5 gallon is not that much different).

 

[geoffm33]

Grain crush can impact efficiency. A finer crush will result in a higher efficiency with the downside being the possibility of a stuck sparge. Since you are BIAB the chances of that are near nil.

If you are milling at the LHBS, do you know if they allow the customers to change the mill roller settings? Same recipe, same ingredients, same water, different crush will have an impact.

If you mill the grain at home, that is one more variable you have control over.

 

[mxchap]

I had a similar problem a few months ago.
Used to hit OG spot on, but then I started noticing low OG and incomplete fermentation (high FG).
Turned out my crummy thermometer went haywire and was reading ~10F lower than reality

Anywho, good luck finding the culprit

 

[notixx]

There are a lot of variables here, and i'm aware that changing more than one at a time doesnt make it easy to narrow that down to one simple solution, but this list of possibilities definitely helps.

I may just need to be more careful with my temps