Raise pH of invert?

[Gadjobrinus]

Been combing invert threads, and though I've seen it touched on, haven't quite landed on the answer. I always made invert 2 according to Ron Pattinson's process. Unless I missed it, I don't recall any treatment to raise the pH post-inversion, though I've seen many do. Can someone tell me the process involved - is it a simple addition of CaCO3, and, if so, is there a formula to calculate how much? Is it even necessary or helpful to final taste?

 

[huckdavidson]

Not an expert (or a chemist) on the subject by any means and I could be completely wrong but:

1.) Lime, NaHCO3 (Baking Soda) and Chalk are the general choices. Lime is usually #1 on the list, followed by baking soda, then chalk. Lime seems to produce the best and most neutral result.

2.) A formula would depend on the acid and the alkali in use. It doesn't require much of either because their isn't a lot of buffering (alkalinity or acidity) in the invert syrup (easy to move the pH up or down). The amount of acid required might be more due to the alkalinity of the source water. It would need to neutralize the waters alkalinity in order to lower the pH of the sugar solution. Also those alkali listed in #1 are chemically very powerful and change the pH fast. A brewing water mash/sparge calculator would most likely suffice for a guesstimate or perhaps a 1/4 - 1/2 tsp of acid and an 1/8 - 1/4 tsp of alkali per 1lb of sugar being inverted.

3.) It's not necessary but some of the benefits would be to a.) stop the inversion process (maintains the color at time of addition), b.) match the wort pH in the kettle (or getting close), c.) render the product safe(r) and more pleasant for consumption raw, d.) microbial resistance, e.) aid in maintaining the syrup state. The Baking Soda and Chalk will most likely leave salts of calcium and sodium behind after the reaction along with the acid anions malate, citrate, lactate, phosphate, chloride, sulfate, etc.... depending on the type of acid used. Most likely not in significant amounts but still something to consider.

 

[Gadjobrinus]

Not an expert (or a chemist) on the subject by any means and I could be completely wrong but:

1.) Lime, NaHCO3 (Baking Soda) and Chalk are the general choices. Lime is usually #1 on the list, followed by baking soda, then chalk. Lime seems to produce the best and most neutral result.

2.) A formula would depend on the acid and the alkali in use. It doesn't require much of either because their isn't a lot of buffering (alkalinity or acidity) in the invert syrup (easy to move the pH up or down). The amount of acid required might be more due to the alkalinity of the source water. It would need to neutralize the waters alkalinity in order to lower the pH of the sugar solution. Also those alkali listed in #1 are chemically very powerful and change the pH fast. A brewing water mash/sparge calculator would most likely suffice for a guesstimate or perhaps a 1/4 - 1/2 tsp of acid and an 1/8 - 1/4 tsp of alkali per 1lb of sugar being inverted.

3.) It's not necessary but some of the benefits would be to a.) stop the inversion process (maintains the color at time of addition), b.) match the wort pH in the kettle (or getting close), c.) render the product safe(r) and more pleasant for consumption raw, d.) microbial resistance, e.) aid in maintaining the syrup state. The Baking Soda and Chalk will most likely leave salts of calcium and sodium behind after the reaction along with the acid anions malate, citrate, lactate, phosphate, chloride, sulfate, etc.... depending on the type of acid used. Most likely not in significant amounts but still something to consider.

For not being a chemist, I´d say that´s a ringer! Thanks much!

 

[kevin58]

This is new to me and I've been making invert for many years... also using Ron Pattinson's process.

 

[brewSJ]

"d.) microbial resistance" -- that one won't work. You'll bet better resistance with a pH below 4.5.
The main use of invert is for baking and its commercial producers (e.g. Ragus) use low temperatures and an extremely acidic environment (pH < 2) to avoid coloring the syrup. With that low a pH you need to neutralize the acid for safety reasons, although there could be other reasons too. They use something (slaked lime?) to neutralize the acid that reacts to form chalk, which then precipitates out of the mixture.

Baker (Journal of the Institute of Brewing, 1902) has a complete description of how brewer's invert used to be made. It's a free download.

 

[brewSJ]

Oops, wrong link. Baker has a good discussion of invert sugar too (and he notes that the taste of inverse is molasses, not caramel), but the link I meant to share was Heron (Journal of the Institute of Brewing, 1896).

 

[huckdavidson]

"d.) microbial resistance" -- that one won't work. You'll bet better resistance with a pH below 4.5.
The main use of invert is for baking and its commercial producers (e.g. Ragus) use low temperatures and an extremely acidic environment (pH < 2) to avoid coloring the syrup. With that low a pH you need to neutralize the acid for safety reasons, although there could be other reasons too. They use something (slaked lime?) to neutralize the acid that reacts to form chalk, which then precipitates out of the mixture.

Baker (Journal of the Institute of Brewing, 1902) has a complete description of how brewer's invert used to be made. It's a free download.

In my (albeit uneducated) mind the necessity of raising the pH (from too acidic, unsafe to eat) to a level which still contributes to microbial resistance (safe to consume but still acidic enough for microbial resistance) would be a property of adding an alkali. Now in the mind a true chemist that may be poppycock.

In fact, as an example, the Ragus process for making Golden Syrup is as follows which appears to leave the final product with a pH above 6.0 (unless of course my aged mind is not fully comprehending):

First, sucrose is heated in an inversion pan with water at 70°. At this stage, 64% of the total sugar required for golden syrup is used, with the solution needing a pH below 1.6 to form a syrup. This is achieved through the inversion of sucrose into glucose and fructose molecules.

The syrup is then polarised to -14 to achieve the desired ratio of sucrose: glucose, before being neutralised with a natural alkaline agent that brings its pH value above 6.0. After, it is further heated in the pan for a set time to caramelise the sugars, resulting in the desired amber colour and treacle flavour.

The remaining 36% of sugar needed for the final product is then added to the inversion pan to produce a partial invert. Once dissolved, the density of the sucrose in the solution is a maximum of 83% and the polarisation is +20.

Next, an alkaline is added to the pan to bind all the non-sugar particles, which are then filtered out through a plate-and-filter press to maximise its purity. Following this, the syrup is stored in maturation tanks.

Finally, the golden syrup must pass through an 80-micron filter before it is packed to customers’ requirements, ready for delivery.