As I travel the country meeting with all types of manufacturers, I hear several common statements and misconceptions about continuous processes. I thought I would try to give a brief explanation to help break down some of these barriers for people.
It is true that there are some processes that will always lend themselves better to a batch process. But let’s see if we can dispel some of the myths.
"We have too many recipes and small runs for it to make sense to go continuous."
This is a common misconception. Small runs with many minor ingredient adds and/or quantity changes make you the perfect candidate for going continuous. As a general rule, as a manufacturer approaches 1 ton per hour of product, changing from a batch to a continuous process starts to pay for itself. This is only ~4 GPM!
One of the easiest and most cost effective ways to start to move toward a fully continuous process is to start with “Late Stage Differentiation” or what we like to call “End of Pipe Mixing”. This is where the final ingredient, or set of ingredients, is added to the base product at the end of the process. This would be like adding the fruit flavoring to yogurt or adding the nuts or “crispies” to chocolate or blending relish or spice blends into a mayonnaise just prior to the depositor.
“We have too many ingredients."
It is true that the more ingredient streams you add to a continuous process, the more expensive and complicated it can be. However, “pre-blending” minor ingredients is an easy way to make a continuous process pay you back quicker.
We recently worked with a company that made various types of muffins. Each recipe had between 32 and 38 ingredients. But all recipes had the same 4 primary ingredients which made up 85% of each batch.
Most of the remaining ~30 ingredients were able to be pre-weighed in a “dries room”. By adding a powder mixing vessel to the dries room, they were able to cut the number of ingredient streams to a maximum of 7 which comprised of 3 liquid ingredient streams and 4 solids ingredient streams.
We were also able to add a large inclusion feeder just prior to the depositor to maintain the highest level of integrity. No more crushed nuts or bleeding blueberries. The flavor has been consistent and the appearance has been improved.
“Our product requires a lot of residence time to fully hydrate."
Long residence times that are required for hydration or even for powders to fully dissolve can be a challenge—but it is not a deal breaker!
This is a common issue with gums, gelatin and or even with applications where sugars and salts need time to dissolve.
Take a starch hydration application where the powder required 3 minutes at 165F to fully hydrate. Our dynamic mixer was able to fully disperse the starch in the liquid but only provided 20 seconds of residence time.
We were able to customize a hot water jacketed hold tube with static mixing elements in the product section to keep the powder dispersed while it traveled through the hold tube. A refractometer was used at the end of the hold tube to verify concentration.
“We already are continuous.”
A truly continuous process means that all ingredients are metered into a common line or dynamic mixer for a single pass process. Your only limitation is the amount of ingredients you have on hand. We like to call this “INFINITE MIXING.”
Metering ingredients into a single tank is a “batch process.” Having multiple batch tanks and emptying one while another batch is being processed forward is still a type of batch process — it is a “continuous batch process.” It is still not considered to be continuous.
Remember that every time an employee touches an ingredient or turns on a machine or takes a sample, there is a chance for human error or loss time incident.
Virtually any ingredient (solid, liquid or gas) can be metered accurately and there are instruments to monitor just about any metric in your process. Density, viscosity, concentration, acidity, pH can all be done inline to keep your process flowing.
"It is too expensive!"
You may be surprised! When you take into to account the higher level of process control, the reduction in labor costs, the higher yields with reduced waste and the reduced footprint, the payback for the conversion to continuous is quicker than you think.
Very few manufacturers do things the same way. Let us share our experience with you to see if going continuous or semi-continuous makes sense for your company.
