View Full Version : Scaling Up Roastiness

08-22-2007, 09:28 PM
Hey everyone, i'm trying to get an idea of whether or not roasted flavour is one of those things affected by scale up.
i'm going to be brewing a stout in the next few days, 25hl(21bbl) system, and got to wondering if there might be a problem here.

any ideas?

also wondering if there is a general rule of thumb when scaling up hops as well...



08-23-2007, 08:49 AM

In my opinion and experience roasted flavors (in fact any flavors from dark roasted malts) are definitely an issue when scaling up. How much of a scale are we talking about? I see that you are going to 21bbl, what size batch is your original recipe?

When we first opened our brewery, we scaled up from 1/2 bbl pilot batches to 7 and 14 bbl production batches. We had to drastically reduce (approx. 50%) the dark specialty malts % of the malt bills to hit similar flavor profiles. However, I'm sure some of the effects were due to differences in our mill/crush/mash tun as well.

If you are not making a huge jump (less than 2-3x) in scale, and will be using the same mill, mash tun, and kettle - I wouldn't worry too much about it.

I can't offer much help with specific guidelines. We used the good old trial and error method to tweak recipes and blended a few batches of beer to achieve the desired flavor/color profiles.

08-24-2007, 07:17 AM
yeah i'm stepping the recipe up from 1/2 bbl to 21bbl. so i'm a little worried about skewing the flavours too much. guess we'll just have to take a stab at it and go from there.

thanks for the response,

08-24-2007, 09:42 AM
Thats quite a scale up. I would not assume anything will scale proportionally for my first assumption. There are so many variables to consider mill efficiency, mash efficiency etc... etc... You might be better off finding someone with a similar size system and share your recipe for comparison to get you in the ballpark. Especially in the dark malt area.

09-01-2007, 12:54 PM
this has always been a quandry for me.
if your intent is to brew a stout @ 10% roasted malt, the O.G. will change this number IMHO.

For example, 10% of 200# is much less than 10% of 350#. A dry stout begining with 10 degrees plato as opposed to an russian imperial begining with 18 plato will give you different %ages based on the total weight of the grist. It is better to determine an amount per Bbl. Figure out your target SRM, etc., and just go from there. If 7# of dark malt is sufficient in one Bbl, then you will need only 28# in 4 Bbl. The base malt should be determined by B.H. efficiency, and extraction figures particular to the malt. This will alter your final number a bit since the dark malt will not be calculated in the equasion.

If anybody knows how to calculate the difference, please explain.


09-03-2007, 03:02 PM
I have used Promash for scaling up or down a few recipes (i.e. 7bbl to 10bbl) This thread got me wondering how accurate it may or may not be for a .5bbl to 21bbl. Anyone have experience using Promash in this manner? Can it accurately compensate for large changes in volume, or does it just increase to scale?

09-04-2007, 06:21 PM
In my opinion, Promash scales pretty well for color (though I find it still slightly underestimates), and hop IBU"s when going from 10 gallon to 15 bbl batches, but not for roastiness. I'm a firm believer in the "less is more" philosophy in scaling up batches.

My first rule of thumb (subject to change) is that if I have a dark malt at say, 5% in the pilot batch, I cut it by about 50% for the first brew...my feeling is that with roastiness, it is better to understate than over do it.