Live Steam Injection Vs. Coil and Jacket (A.k.a Ford vs. Chevy)

[david@nederlandergroup.com]

First, forgive me if I'm posting something that exists within these threads. I've done searching and found a lot of indirect information but nothing that rounds out what I'm looking for.

We are designing our system and have the opportunity to go with either setup for our mash cooker. Right now our plan is to use direct steam injection but I've received a lot of criticism from other distillers who state that introducing steam that could have possible contamination from boiler treatment (even if it is food grade) is a big mistake. The other side of the argument is that we've (the royal we) been making whiskey in America for 60 years using live steam injection. It's efficient and works, so why change it.

The alternative is to use internal coils running indirect steam in combination with a dimple jacket for cooling water.

*We are using a low pressure Colombia boiler

If you could set this up however you wanted, what would you do and why?

Thanks in advance.

[Silk City Distillers]

Between DSI and Coils for a mash tank, in my book DSI wins. Cleanup is easier with DSI, no mixing dead spots with DSI, retrofit/fab on an existing tank is much easier when you don't need to deal with condensate return on the coils. DSI is also going to be more efficient, as long as you keep the steam fully condensing in the tank.

The downside to DSI - big culinary steam filters are expensive, and you need to be using compatible chemicals, pretreat and use no chemicals at all (cue boiler additive distributor outrage).

Culinary grade steam is regularly used in food manufacture, in direct food contact and in food cooking. If it can be used in this application, which has a much higher level of scrutiny (you are eating what's coming out of the boiler), I don't see how mashing with DSI could be considered problematic ... if you follow a similar protocol. Also consider that the fermented mash will be going through an additional distillation stage, eliminating any non-volatiles or particulates introduced.

[John McKee]

David,

One other note about DSI. If the steam is coming directly from the boiler and not being produced secondarily via a a heat exchanger you also have the problem of boiler tube corrosion.

Single pass water through a boiler exhausts its oxygen and pits out tubes pretty quick. I've seen boilers loose tubes in fewer than 2-3 years from this kind of usage. You can get around it with SS tubes, but those make your boiler pretty darn expensive.

If you're going to do it right, use a secondary loop with a heat exchanger to create steam from a different source and allow your boiler to run in a closed loop, which overall is a much cheaper and efficient long-term use of a steam boiler.

Cheers,

McKee

[david@nederlandergroup.com]

John and James - thanks for your input.

Not to be argumentative but it seems like the the systems needed in order to use DSI add some layers of complexity (either secondary loop OR culinary grade steam filtering). I realize that having any coils in the mash tank create an issue with cleaning but also allow my mechanical systems to run on completely closed loops.

If I'm missing something else, let me know. Thanks again!

[John McKee]

David,

I run everything on closed loops, jacketed mashtun (no coil), external heat exchangers for our stills (no direct steam injection), etc. Just keeps everything simpler in my mind for some reason. I know plenty of people who use DSI, just wasn't my flavor.

Cheers,

McKee

[david@nederlandergroup.com]

Thanks John - Just to clarify, on the mashtun are you using the jacket for heating and cooling or an external heat exchanger for the cooling?

Thanks again!

[John McKee]

David,

We use the same jacket for both. Steam for heat-up, throw the manifold valves and use cooling water through the jacket for cool-down. Rinse, repeat next mash.

Cheers,

McKee

[Silk City Distillers]

Jackets win over DSI and Coils, but if you are going to use your jacket for dual duty of heating and cooling, you better be sure it's designed to handle the thermal stresses of rapid cooling.

I could easily see a dimple jacket failing prematurely due to fatigue In fact, most manufacturers will tell you that unless you've informed them of thermal shock being a requirement, they aren't going to warranty the tank or jacket at all.

[Scrounge]

There are manufacturers that put in separate jackets for heating and cooling. Check Corson Distilling. I have a 300g tun from them and I absolutely love it. Does exactly what they designed it to do. It's so simple I don't know why you would want to mess with coils or dsi. But I guess I only know a lot about a little.

[Silk City Distillers]

I think most folks asking about DSI or coils are retrofitting an existing tank.