It would be really useful to be able to see if there is a substitution for a given stock item and the stock of that substitution ingredient.
It could flag up telling you that you have enough in stock if substituted but not if you want to use the original ingredient etc.
This way you can decide which you might want to use first and not over order on ingredients.
Very popular feature at your place. 
And ideally make it easy to order a sub rather than the original
Please make this happen!
Another thing with subs which would be useful is the ability to use subs even if you have the original ingredient in stock.
This sounds like a great suggestion, Ben, but it will need its own feature request as it’s technically a completely different feature (although I appreciate that they both relate to substitutions). Could you please post this in a new thread so it doesn’t get lost in this thread? Thank you.
Hi Luke,
Can you confirm why this suggestion is closed but not marked as completed?
It’s not closed (or completed)?
Weird the vote button was saying closed for me just now.
Oh, sorry, I’m not sure why that might have been. It’s showing correctly for me, and I’ve never noticed it not in the past. If we hear of this issue again, we’ll raise it with our community software provider 
Here are a couple situations we’re running into:
We have a few domestic base malts from different maltsters that we treat as interchangeable for recipe purposes (they have the same flavor in the finished beer), but they behave slightly differently in the mash tun (small change to mash efficiency and pH). We need to know what we’re brewing with to make adjustments, so we need to treat them as separate stock items, but we essentially treat them as a single pool for assigning stock to batches. When we go to order malt, we need to see how much we have of each of these stock items, so we can see what we need to purchase from whichever supplier we’re getting a pallet from.
Then for hops, we use T90 and T45/Cryo/CGX pellets nearly interchangeably. We of course have a conversion rate, and most recipes have a preferred format, but if we have the other format available, we’ll use what we have first. We need to be able to see how much we have of the other format (with conversion applied) when determining what to order.