calculating efficiency for partial mash brews?

[founddrama]

I found this old post which is asking roughly the same question, but there were no replies and I thought I'd ask here.

I do quite a bit of partial mash brews with late-addition extract added to help hit the O.G.'s that I want. What I'm running into is that when I take my gravity readings, I'm doing so after the mash has completed but before I've added the extracts. I'm finding that BeerSmith will show me an estimated post-mash gravity like 1.082 but what I actually get is something closer to 1.050 (with the remaining points coming late in the boil from the extract).

Is there a setting that I've missed that can account for this? Or should I create two versions of the recipe (one with the extract and one without) -- as a hack to get around this? What are other people doing to calculate their mash efficiencies when partial mash brewing?

[brewfun]

The new version of BeerSmith (2.3.X) has a "post mash gravity" field found in the Session tab. This is the expected wort gravity once the mash & sparge are complete. The Preboil field should reflect the addition of extract and/or any other kettle sugar additions, even if they're added late in the boil.

[founddrama]

The new version of BeerSmith (2.3.X) has a "post mash gravity" field found in the Session tab. This is the expected wort gravity once the mash & sparge are complete. The Preboil field should reflect the addition of extract and/or any other kettle sugar additions, even if they're added late in the boil.

Hmm... what you're saying makes sense but that's not what I see. I'm running BeerSmith 2.3.7, and I picked 3 of my most recent partial mash formulations, all with only late-addition extracts, and in each case, the "Post Mash Gravity" and "Est Pre-Boil Gravity" fields give identical numbers (i.e., 1.082, 1.092, 1.078 -- respectively).

I'll keep digging, but either I've got something configured wrong or these fields aren't getting calculated independently.

[KellerBrauer]

I guess I'm confused.  As I see your question, the Post Mash and Pre Boil should be exactly the same.  If you add additional sugar at, or toward, the end of the boil you shoild see those additions in the OG field.

[Oginme]

The new version of BeerSmith (2.3.X) has a "post mash gravity" field found in the Session tab. This is the expected wort gravity once the mash & sparge are complete. The Preboil field should reflect the addition of extract and/or any other kettle sugar additions, even if they're added late in the boil.

Hmm... what you're saying makes sense but that's not what I see. I'm running BeerSmith 2.3.7, and I picked 3 of my most recent partial mash formulations, all with only late-addition extracts, and in each case, the "Post Mash Gravity" and "Est Pre-Boil Gravity" fields give identical numbers (i.e., 1.082, 1.092, 1.078 -- respectively).

I'll keep digging, but either I've got something configured wrong or these fields aren't getting calculated independently.

If you are adding your extract late in the boil, then the post mash and pre boil gravity SHOULD be the same.  If, however, you add the extract at the beginning of the boil or between collection of wort from mash and the boil the gravity from post mash IS different from the pre boil gravity, as it should be.

[brewfun]

I guess I'm confused.  As I see your question, the Post Mash and Pre Boil should be exactly the same.  If you add additional sugar at, or toward, the end of the boil you shoild see those additions in the OG field.

BeerSmith counts sugar additions in the kettle as part of Preboil gravity. I just checked. I then changed the sugar to an extract and the same behavior remained true. The mash gravity in both cases was 1.072 and the preboil gravity was 1.077. Removing the extract from the recipe showed both mash & preboil gravity at 1.073. This behavior remained true in both all grain and partial mash assignments.

This is consistent with how BeerSmith 2.2 operated, where all sugars were part of the preboil number, regardless of source or when they were added.

If a grain, extract or sugar is marked as being added after the boil, then the gravity does not show up in the preboil number, and this is new behavior in version 2.3. It'll show up in the OG, instead.

The extract (or sugar) must be categorized in the ingredient details as sugar, extract or dry extract for it to be properly assigned to a kettle addition, instead of mash. If marked as grain or adjunct, then BeerSmith assumes it will be part of the mash.

[brewfun]

If you are adding your extract late in the boil, then the post mash and pre boil gravity SHOULD be the same. 

This doesn't seem to be the case. Can you check me on this? I added and extract addition and marked it as added with 10 minutes to go in the boil. The mash gravity and preboil gravity show the same, but the post boil OG reflects the added extract.

Are you seeing different behavior?

[KellerBrauer]

Thanks for the info Brewfun.  I understand what you're saying, but it is not logical for sugar to be calculated before its added.  But, okay.

[Oginme]

If you are adding your extract late in the boil, then the post mash and pre boil gravity SHOULD be the same. 

This doesn't seem to be the case. Can you check me on this? I added and extract addition and marked it as added with 10 minutes to go in the boil. The mash gravity and preboil gravity show the same, but the post boil OG reflects the added extract.

Are you seeing different behavior?

I made a partial mash recipe with 0.5 kg of both preboil DME and late extract additions with 1 kg of 2-row 

2-row only:  post mash 1.019,  Pre-boil 1.019,  Post boil 1.024

2-row & pre-boil addition of DME: post mash 1.019, pre-boil: 1.033, post boil: 1.043

2-row & late dme add: post mash: 1.019, pre-boil, 1.019, post boil: 1.043

2-row & pre- + late DME adds: post mash: 1.019, pre-boil: 1.033, post boil: 1.062

It seems to be working consistently.  Even checked some of the numbers by hand.  This is how it should be working.