Determining the Alkalinity of Cocoa Ash


Chocolate is made from cocoa beans and, although it was originally a delicacy, is enjoyed in many forms all over the world. Cocoa was widely used in South America by the Mayans, and later was brought to Spain where its popularity grew. Over time, “chocolate houses” started opening throughout Europe, followed by the production of confections from cocoa beans. Today more than 3 million tons of cocoa beans are consumed annually, with 90% being produced on small farms. Consumption of cocoa beans varies from chocolate cake to hot chocolate, and includes a myriad of treats enjoyed around the globe.

Monitoring Acid and Iron in Steel Pickling Baths

Due to its high resistance to corrosion, stainless steel is used in a variety of industries, from cutlery and kitchenware to oil and gas. Various grades of stainless steel exist that are based on the concentrations of constituents such as chromium, nickel, and carbon. In order for a metal to be classified as “stainless steel,” there must be a minimum of 10.5% chromium by weight. When stainless steel is subjected to an oxygen-rich environment, such as air or aerated water, a chromium-rich oxide layer develops on the surface. This outer chromium oxide layer protects the product from corrosion that may occur as a result of scaling and rusting. Prior to the formation of the oxide layer, the stainless steel is subjected to several surface treatment processes to remove surface imperfections and impurities. These treatment processes include descaling, pickling and passivation. During the pickling stage, the impurities on the surface of stainless steel are removed. The steel is placed in an acid pickling bath consisting of various additives that partially dissolves the outermost layer of the steel product, exposing a fresh, pure surface. Steel pickling baths generally consist of either a single acid, such as hydrochloric acid, or a mixture of acids, such as nitric acid and hydrofluoric acid.

Over time, pickling baths become contaminated with dissolved metals that were stripped from the steel product. As the concentration of dissolved metals increases, the free acid concentration in the bath decreases, causing a decrease in the efficiency of the pickling process. The free acid concentration in a bath indicates the amount of acid available for the pickling process. When this concentration drops below a certain threshold, additions of acid are made to ensure there is sufficient free acid available. The total acid concentration of a bath is the concentration of both free acid and spent acid that is no longer available for pickling. Once a certain limit of spent acid is reached, the bath are drained and replaced with fresh chemicals.

In addition to having quality limits for free and total acid levels, pickling baths must also maintain a certain oxidizing potential. The concentrations of ferric (Fe³+) and ferrous (Fe2+) iron dictate the oxidizing power of the pickling bath. The oxidizing power affects the time required for pickling and the quality of the finished product. If the levels of total iron are too low or too high, or the ratio between ferrous and ferric iron is skewed, the pickling process becomes ineffective. To adjust the ferric to ferrous ratio, oxidizers such as hydrogen peroxide may be added to the bath to oxidize ferrous iron to the ferric form. Generally the ideal ratio of ferrous to ferric iron is 3 to 4.


A stainless steel processing company contacted Hanna Instruments in search of an automatic titrator for analysis of their hydrochloric acid based pickling bath. In the past, the processing company performed manual titrations for the determination of free and total acid as well as ferric and ferrous iron, but they were looking to automate and simplify their process. Hanna Instruments recommended the HI902C Potentiometric Automatic Titrator with two analog boards, two pumps, and two burettes. For free and total acid determination, Hanna Instruments supplied the HI1043B pH Electrode for use in strong acids. The customer utilized sodium hydroxide (NaOH) as the titrant and titrated to a fixed endpoint of pH 4.2 for free acid and pH 8.6 for total acid. For free and total acid determination, two separate methods were created. Using the “Linked Method” option equipped on the HI902C, the “Total Acid” method was linked to the “Free Acid” method, where upon completion of the “Free Acid” method, “Total Acid” would begin either immediately or upon a manual start. Because the customer was utilizing a fixed pH endpoint for two of their analyses, Hanna instructed them to frequently calibrate their pH electrode to three points in order to ensure accurate results. For the determination of ferrous iron, the customer was previously performing an oxidation-reduction titration to a color endpoint. In this reaction, ferrous iron is oxidized by a potassium permanganate (KMnO₄) titrant. Hanna Instruments supplied the HI3131B ORP Electrode for use with the HI902C to automate their titration. Due to better chemical stability, Hanna recommended the customer change their titrant from KMnO₄ to cerium (IV) sulfate (Ce[SO₄]₂), allowing them to standardize their titrant less frequently and maintain accurate results. After the customer performs their acid and ferrous iron titrations, the concentration of ferric iron is then inferred from the results by subtracting the ferrous iron concentration from the difference between the free and total acid content. The customer was very pleased with the knowledge and technical support they received from Hanna Instruments, and felt confident in their purchase.

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Determination of Organic Chlorine in Crude Oil with the HI902C Potentiometric Titration System According to ASTM D4929

Crude oil is a term for unrefined petroleum, a naturally occurring liquid found in geological formations beneath the earth’s surface. Crude oil can be refined into several valuable types of fuel including petrol, jet, and diesel fuels. Crude oil is ideal for the production of these high-energy fuels, as it contains a large quantity of hydrocarbons. The combustion of these hydrocarbons with oxygen produce the energy needed to operate boilers, engines and other machinery.

Measuring the Salt Content of Bread


The art of bread making has a rich and extensive history, with ancient roots that can be traced back at least 30,000 years. Today, the cultural and nutritional importance of bread is still significant as it continues to shape culinary identities worldwide. Generally, the process of bread making remains unchanged. Unleavened breads, such as Matzoh, are comprised of only flour and water. Upon mixing, gluten protein is formed, giving the bread structure and elasticity. After the dough is kneaded, it is baked immediately and results in a thin “ flat bread”. In comparison, leavened bread is that which rises during the baking process due to the addition of a leavening agent.

Monitoring Moisture Content in Spices


Over the past few years, with the popularity of cooking shows, there has been an increasing trend of people experimenting more with flavors and tastes. One way that people experiment in the kitchen is through the use of spices and herbs. Considering the International Organization for Standardization (ISO) identifies over 100 varieties of herbs and spices, there are many different options for flavor combinations.

Determination of Protein Content in Milk through Total Kjeldahl Nitrogen Analysis


Proteins are macromolecules that play a crucial role in nutritional growth and development. These large biological molecules contain at least one long chain of amino acid residues and are responsible for a multitude of biological functions, including DNA
replication and repair, catalyzing metabolic reactions, and providing structure and communication in and between cells. The digestive breakdown of proteins into amino acids provides an important source of fuel and dietary nitrogen. Milk naturally contains a number of key nutrients, including protein, which is beneficial to humans regardless of their age. Globally, milk is a commonly consumed food product that, due to its high nutrient composition, is regarded as highly beneficial for growth. In cow and sheep milk the percent protein can range from 3.3% to 5.8%.

Mini Automatic Titrator for Dairy

We’re pleased to announce the release of a new mini automatic titrator designed specifically for the dairy industry.

The new titrator, HI 84529, is designed specifically for testing the acidity levels and pH in dairy products.

It features a high precision piston dosing system with dynamic dosing and compact, space saving footprint.  It also feature automatic stirrer speed control, a graphic mode with exportable data and a Good Laboratory Practices (GLP) feature which allows users to view calibration data.

Hanna Instruments manufactures a variety of analytical instrumentation for the food and beverage industry, including juice meters, dairy meters, wine meters and more.
Hanna’s new mini titrator is available through any of our 40 international locations.  These offices provide Hanna customers with local service, support and training and are part of Hanna’s goal to provide an exceptional customer experience.

For more information on this and other Hanna Instruments titrators, click here.

Titration Knowledge Base Videos

We’ve uploaded some new Knowledge Base videos demonstrating the features of our automatic titration systems.  These short videos give you a quick overview on how to setup and access a titration report, transfer files to a USB drive and exchange our Clip Lock™ Burettes.

Hanna Instruments offers a full line of automatic titrators, including both potentiometric titrators (HI 902) and Karl Fischer Titrators (HI 903) for moisture analysis. These accurate, affordable titrators are the perfect way to streamline your titration process.

Here are links to our latest Knowledge Base videos:

Knowledge Base: Accessing a Titration Report on the HI 902

Knowledge Base: Setting Up a Titration Report on the HI 902

Knowledge Base: Transferring Files from the Titrator to USB Drive

Knowledge Base: How to Exchange Clip Lock™ Burettes

Check our Youtube channel regularly for updates and new videos.

Hanna Instruments Releases Redesigned Sulfur Dioxide Mini Titrator for Wine Analysis

We are pleased to announce our latest product, the HI 84500. The HI 84500 is the latest in Hanna’s line of Mini Automatic Titrators.   It is a simple, fast and affordable mini automatic titrator designed for testing free or total sulfur dioxide (SO2) levels in wine.

This titrator features a highly accurate piston dosing system, improving accuracy over the previous model.  The HI 84500 can also be used as an mV/ORP meter for direct measurements. It replaces the HI 84100.

For more information on the new HI 84500, click here.