OnTap Magazine

While the process is quite straightforward, as soon as you layer in all the nuances that take an “okay” product and make it great, those same processes and controls begin to get more challenging. First, the milk: store- bought, pasteurized milk doesn’t cut it, especially when making a delicate cheese like fior de latte. Good luck trying to stretch those curds when the proteins have been annihilated by commercial pasteurization. Finding a raw milk source was a huge challenge, one made even more difficult when trying to dodge roadblocks between the brewery and the farm during hard lockdown. Also, for the fior de latte to have any decent flavour, the milk needs a high-fat content, so ideally you need a South African farmer who primarily farms Jersey cows. (To note: the selling of raw milk in South Africa is “frowned upon,” so ensure you have some sort of “liquid leverage” on hand to sweeten the deal for the farmer...) The main reason to use raw milk is because you can then pasteurise it on your own terms. A low-temperature, long-hold pasteurization will ensure the milk is safe for consumption, all the while preserving protein structure. This makes for a much more forgiving production process, meaning it helps ensure stronger curd formation and better stretchability when producing the cheese. WHERE IT GETS TRICKY… This is where some of the brewery equipment came into play. The wort heat exchanger, which is a piece of equipment designed to transfer heat energy from one liquid to another, was perfect for raising and cooling the milk temperature. Normally, in a brewery, cold water or propylene glycol will be used to achieve the transfer of heat energy, but in our situation, this was substituted for cold milk. This aligned well with a normal brew day as the cold milk was used to cool the hot wort on its way to the fermenter, with the benefit of the milk reaching pasteurization temperatures at the same time. Next is the curd acidity, indicated by the pH value. For mozzarella to stretch it needs to be in the correct pH range which, unfortunately, is very narrow. Start the heating and stretching phase too early or too late and the curds will either fail to come together, or be left with a big ball of curd-like mush. A pH meter should help, however, we often found it inconsistent. The only way we managed to achieve consistency was to go by feel, and to teach ourselves the signs indicating that the curds were ready. This resulted in many failed attempts, as you can imagine, but thankfully, we got there in the end. One thing to remember is that the curds might be at the perfect point to process, however processing 30-40kg of cheese by hand is very time-consuming. The culture waits for no one and continues to produce lactic acid further dropping the pH out of the desired range; best to make sure you work quickly and stagger the process so that the perfect stretched period is not overshot. REPURPOSING BREW EQUIPMENT ontapmag.co.za | Winter 2023 | 31