I have a few BIAB 10 litre batches under my belt and am currently investigating the BIABacus. I'm doing so by plugging in a couple of BeerSmith recipes that I'd previously brewed, as well as mapping out the next two brews I have in the pipeline, a Brown Ale followed by a Fullers 1845 clone.

My last batch was a 1.085 Doppelbock. I'm not going to make a habit of brewing beers this big, mostly because I don't really enjoy drinking strong beers, but thought it would be an interesting project nonetheless.

I used Beersmith to plan the recipe and guide my brewday.

I had been getting EIB figures of around 85% on my 1.050 beers and whilst I expected a drop of efficiency with this higher OG beer, I underestimated the extent.

After the mash, I realised I was at 70% EIB instead of the 80% that I'd based the recipe on and so with the help of Beersmith, worked out that 250g of DME would get me to my target OG. I added the DME at the end of the boil and hit my target OG of 1.085.

I've been playing around with the same recipe in the BIABacus, just to get a feel for how the same brew would look and as a way of building up a collection of BIABacus files for previous brews.

Now, first of all, I realise that the BIABacus "auto-adjusts" for decreased efficiency for larger grain bills. I really like this feature and as I play with different target OG's realise that it closely matches my EIB figures for different batches at different OG's. I also realise that I can tweak this via Section X to more closely match my system. For now it seems close enough.

But the one thing I'm stuck on at the moment is the scenario where I added DME, not as part of the original fermentable bill, but as a post-mash adjustment.

I have been playing with Section N: Pre-Pitching Corrections where there is a field for DME additions by way of an adjustment.

Alternatively, if my EIB was lower than expected, I could have increased the boil time, but again, I'm not sure how to make these mid-brewday adjustments in the BIABacus without the grain bill being altered.

So the scenario is where my EIB is lower than expected, is there a way via the BIABacus to calculate how much DME additions and/or increased boil time will get me to my desired OG?

Maybe this is a moot point due to the BIABacus auto-adjusting my EIB based on the OG of the beer, and this scenario won't really arise, where I need to make adjustments on the fly due to incorrectly estimating my mash efficiency. The BIABacus would have got me closer to my actual EIB.

Maybe I just need to look forward and not try and shoe-horn previous brews into the BIABacus which is what it feels like I am doing.

Ah, thanks MS — that's interesting about "safe" mode. I'll bear that in mind.

I think the best approach for me right now is to look forward to my next batch, not backwards to past batches and stick with the defaults, except for evaporation rate.

I'm planning a Northern Brown Ale right now so maybe if I post that file once I have it locked down — I assume I would do this in the "recipe planning" thread?

The only issue here is I already have the grains on hand, weighed and milled, so am tweaking my BIABacus volumes to line up my existing grain bill and OG with the default BIABacus auto kettle efficiency.

Thanks MS.

Recipe file attached.

The recipe is based on Cigar City's Maduro Brown Ale, but I'm not looking for an exact clone.

As mentioned, I already have the milled and bagged grains on hand, so I've tweaked my volumes to fit my estimated OG and BIABacus kettle efficiency figure.