Water level in recipes

Hello Everyone.
I've been reading and reading recipes all around and I have stumbled upon some things I don't understand.
Here are some:

- When I read the recipe the batch size is 18.93 l. In the mash instruction section it says to add 10 l of water at Xº temp and later add water to achieve 25.70 l of wort. My question is, the gravity of the 10 l of infused water will have enough density so when I add 15 l of water the SG will be around the estimated parameters? Or is it a glitch in the recipe? or the conversion units are not set up properly? Am I reading the steps incorrectly?

- At the beginning of the same recipe, the total amount of water to be used is 30.74 l. The amount of water needed for the the Mash In is 10.65 l and in the Fly Sparge is 20.09 l. If I add both quantities (10.65 + 20.09) that gives me 30.74, so i can assume that I have to do the Mash In and the Fly Sparge one after the other. Because it says "Add water to achieve boil volume of 25.70 l" I should expect a lost of water higher than 5 l?

- If the batch volume is 18.93 l, why the final bottling volume is 17.41 l?

I'm from Chile, so my "technical" english is not the greatest so forgive me if something is not clear.
Cheers and hope you can help me.

Your English is fine.  Without knowing the target gravity readings, it is difficult to give you an answer.  You should have a target gravity from the mash, a target gravity after the water addition and a final OG target.  With those numbers, maybe we can puzzle out the water additions.

The OG 1.048 SG
Estimated Final Gravity is 1.009 SG.
Thanks

OK, I think I get it now.  I am assuming that you are looking at a recipe in BeerSmith written for someone else's equipment profile.  The first thing you need to do is to "scale" the recipe into your equipment profile and see where the water levels come out.

Basically, what the existing recipe is telling you is that you want to add 10.65 liters of water to the grain for the mash.  This seems really low to me, but we can work with that. 

Some of that initial water will be absorbed by the grain and fill any 'dead space' of your mash tun (volume which cannot be drained out of your mash tun). 

After the mash, you will be fly sparging with approximately 20.09 liters of water.

The 'add water to achieve 25.70 liters' is generic and covers any variation in water collection from the mash and sparge water combined.  It simply states what your goal is out of the mash tun from the combined mash and sparge drainings and lets you know to add water to get to your pre-boil volume.  This is optional and depends upon your combined gravity.  It is not expecting the loss to be greater than design as indicated with the equipment profile, but is there to compensate if it is.

Batch volume in BeerSmith is the volume of wort into the fermentor.  From that volume there will be some loss to trub and yeast at the bottom of the fermentor.  Thus, your net volume out of 17.41 liters for bottling.

I hope this helps in explaining the process.  Let me know if you have any more questions or if something I said was unclear.

Greetings pugalde,

If I understand your question, the losses you are mentioning are due to trub loss and grain absorption. However, where BS asks to "add water to achieve 'X' volume" also confused me also. In my mind, and if the parameters in the Equipment Profile are correct, additional water should not be needed.

So, what I have done to overcome this anomaly is to simply tweek my equipment profile until my boil volume and my bottling volumes are both accurate.  Doing so has made my previous 5 batched hit their target each time.

Thank you both for the quick answers. It's clearer now. Is all down to the equipment I am using.
Im going to set that up, give it a go and check if everything is correct. Thanks again.